Question Can I swap out the C drive from another similar PC ?

[Tim042]

If i have a Windows 7 computer that is happily running with its own installed drive and the Key activated and i swap out another C drive from a different PC into it with the same OS type, will nothing happen OR will it only ask for "click" to activate or fully lock up and tell me to call MS as it detected wrong drive?

And If i don't ring them or do anything but swap the correct drive back in, will it reactivate now and all be good again or stay deactivated?

I ask these questions as I have a number of same computers with their own activated Keys and if mine was to fail, i could at least temporarily swap my C drive into another PC with same M/B (diff serial number) and would it detect different C drive even if all the drivers should work as hardware is basically the same?

Yes, I understand to fully have Comp B working right, i would have to "migrate" that C drive and its programs to match the new computer, but temporarily until i do all that, would it cause a MS key conflict as Comp B already has its key activated to its own M/B. I'm only swapping out a c drive from a similar computer temporarily.

I'd like to get my head around what MS servers look for when it checks "Hardware" against what it has in memory and if a diff C drive would be enough to cause key failure? even if the C drive would cause B computer to run a bit wonky.

 

[USAFRet]

If i have a Win 7 computer that is happily running with its own installed drive and the Key activated and i swap out another diff comp C drive into it even with same OS type, Will nothing happen OR will it only ask for "click" to activate or fully lock up and tell me to call MS as it detected wrong drive and B, If i dont ring or do anything but swap the correct drive back in, will it reactivate now and all be good again or stay deactivated?
Ask this question as i have a number a same computers with their own activated Keys and if mine was to fail, i could at least temp swap my C drive into another with same M/B (diff serial number) and would it detect diff C drive even if all the drivers should work as hardware is basically the same.
Yes, I understand to fully have Comp B working right, i would have to "migrate" that C drive and its programs to match the new computer, but Temp until i do all that, would it cause a MS key conflict as Comp B already has its key activated to its own M/B. Only swapping out a c drive from a similar computer temp.

Like to get my head around what MS servers look for when it checks "Hardware" against what it has in memory and if a diff C drive would be enough to cause key failure? even if the C drive would cause B computer to run a bit wonky.

Moving an OS to a different system, it will absolutely become Unactivated.

Win 7, the license is strongly linked to the system/motherboard.

And as the Windows 7 activation farm is no longer viable....it is unlikely you can influence Microsoft to activate this after moving to different hardware.
"click to activate" is no longer a thing.


What exactly are you trying to do, and why?

 

[ex_bubblehead]

That drive you swap in will immediately complain that Windows is not activated and require a call to Microsoft (the activation servers were taken offline years ago). Don't count on getting a new activation code. You cannot simply swap drives at will. And, you cannot put that drive back into the original machine as Windows will no longer be activated at that point.

 

[Tim042]

That drive you swap in will immediately complain that Windows is not activated and require a call to Microsoft (the activation servers were taken offline years ago). Don't count on getting a new activation code. You cannot simply swap drives at will. And, you cannot put that drive back into the original machine as Windows will no longer be activated at that point.

thanks for your reply. So only way i can move over to another computer even if same specs is a "migrate" using a program transfer program deal which i have done before and you have to choose what programs and settings ect and prepare the current drive to assimilate all the c drive stuff from old computer using a transfer file or cable.
Interesting, when you clone that original c drive, you can hot swap it into same computer and it will boot and act totally the same, so the clone Program must prepare that drive so not only bit for bit but what it needs so the MS servers dont see it as a "different" drive? Used boot clones many times and they work 100% but only on same Computer which can suddenly break and asking question as might need to swap quickly if in middle of a stock trade haha or something..

 

[USAFRet]

thanks for your reply. So only way i can move over to another computer even if same specs is a "migrate" using a program transfer program deal which i have done before and you have to choose what programs and settings ect and prepare the current drive to assimilate all the c drive stuff from old computer using a transfer file or cable.
Interesting, when you clone that original c drive, you can hot swap it into same computer and it will boot and act totally the same, so the clone Program must prepare that drive so not only bit for bit but what it needs so the MS servers dont see it as a "different" drive? Used boot clones many times and they work 100% but only on same Computer which can suddenly break and asking question as might need to swap quickly if in middle of a stock trade haha or something..

The OS must stay on the motherboard it is currently on.

If the only difference is "applications", simply install whatever applications you need on the other system.
'program transfer' things often fail. And fail badly.


Cloning between 2 drives in the same system is no problem. The drive is irrelevant as regards the licensing. The rest of the system is what counts.

 

[Tim042]

I guess what i am getting at is.... HOW does/do the servers tell the diff between original C Drive A with win 7 and C drive B with win 7 from diff computer? Do the H/Ds also have serial numbers or is there data on the original Drive that it reads and will see another c drive as "foreign" I guess cloning would include this info as its a diff drive but MS happily accepts it but not another c drive from diff computer with same OS?

 

[USAFRet]

I guess what i am getting at is.... HOW does/do the servers tell the diff between original C Drive A with win 7 and C drive B with win 7 from diff computer? Do the H/Ds also have serial numbers or is there data on the original Drive that it reads and will see another c drive as "foreign" I guess cloning would include this info as its a diff drive but MS happily accepts it but not another c drive from diff computer with same OS?

Mostly, the motherboard.
Drive and OS A, with motherboard X.
Move that drive+OS to a different motherboard Y, problems.

Clone or physical drive, makes no difference. Problems will ensue.

 

[Tim042]

i totally understand that in practice but HOW does it differentiate between a clone drive and another computers drive if BOTH are physically diff drives.

 

[USAFRet]

i totally understand that in practice but HOW does it differentiate between a clone drive and another computers drive if BOTH are physically diff drives.

The OS knows what motherboard (and other system parts) it was linked to.
Either on the original drive, or a clone of it.

Connecting to a different motherboard, different serial number. (and no, you can't change this)
It will Unactivate itself.


Cloning to a new drive in the same system is totally fine. Happens all the time, no problem.
A clone, then being installed in a different system...problem.

 

[Tim042]

The OS knows what motherboard (and other system parts) it was linked to.
Either on the original drive, or a clone of it.

Connecting to a different motherboard, different serial number. (and no, you can't change this)
It will Unactivate itself.


Cloning to a new drive in the same system is totally fine. Happens all the time, no problem.
A clone, then being installed in a different system...problem.

So i guessing the clone drive although a diff drive and serial number, must have some code/data written to it to "appear" same c drive and boot and load totally normally. Normally you clone your C drive using the same Computer you are cloning the drive too. What would happen if i used a diff computer B to clone computer A's drive to another drive (using a caddy) and then put that clone drive into comp A. would it work, as it used a diff computers OS to do the clone? I wonder if anyone can answer this question. I might have to try it as a thought experiment haha
Afterthought- MAY only be possible to clone a c drive using that computer and not another as the program may require the c drive to be there in place but you can use a caddy ect to clone to another drive. I have only ever done this of course but interestingly when i used Macrium, it didnt like me cloning to a SSD, but disk Genius no problem. I used that program ever since!!

 

[USAFRet]

So i guessing the clone drive although a diff drive and serial number, must have some code/data written to it to "appear" same c drive and boot and load totally normally. Normally you clone your C drive using the same Computer you are cloning the drive too. What would happen if i used a diff computer B to clone computer A's drive to another drive (using a caddy) and then put that clone drive into comp A. would it work, as it used a diff computers OS to do the clone? I wonder if anyone can answer this question. I might have to try it as a thought experiment haha
Afterthought- MAY only be possible to clone a c drive using that computer and not another as the program may require the c drive to be there in place but you can use a caddy ect to clone to another drive. I have only ever done this of course but interestingly when i used Macrium, it didnt like me cloning to a SSD, but disk Genius no problem. I used that program ever since!!

As long as you're not booting from that drive in a different system, no problem.

 

[stuff and nonesense]

Ask this question as i have a number a same computers with their own activated Keys and if mine was to fail, i could at least temp swap my C drive into another with same M/B (diff serial number) and would it detect diff C drive even if all the drivers should work as hardware is basically the same.
Yes, I understand to fully have Comp B working right, i would have to "migrate" that C drive and its programs to match the new computer, but Temp until i do all that, would it cause a MS key conflict as Comp B already has its key activated to its own M/B. Only swapping out a c drive from a similar computer temp.

Depending on how many computers you have cloning the boot drive for each of the systems would provide you with the redundancy you appear to be looking for. Each cloned drive would be keyed to a specific system. Only use the clone drive in its “source system” as activation would likely be lost otherwise.

In work a number of years ago this regime was implemented:

C drive, OS and registry - cloned drive refreshed (overwritten) after changes (new programs) or 6 monthly.
D drive, Programs - backed up and updated on changes
E drive, Data - backed up 3 times a week.

Automatic updates would have caused more regular C drive cloning cycles. Our kit was on its own isolated network and had no internet connection.

 

[Tim042]

Depending on how many computers you have cloning the boot drive for each of the systems would provide you with the redundancy you appear to be looking for. Each cloned drive would be keyed to a specific system. Only use the clone drive in its “source system” as activation would likely be lost otherwise.

In work a number of years ago this regime was implemented:

C drive, OS and registry - cloned drive refreshed (overwritten) after changes (new programs) or 6 monthly.
D drive, Programs - backed up and updated on changes
E drive, Data - backed up 3 times a week.

Automatic updates would have caused more regular C drive cloning cycles. Our kit was on its own isolated network and had no internet connection.

Hi S & N. Thanks for reply, i have read it a few times and i know its right, i just not quite getting it or i might have confused you as i can get a bit wordy.

I will try to clarify as i think this is extremely useful question

Scene- Computer A and B are all identical in that same M/B with same REV 1.0 BUT obviously the serial numbers are diff and thus MS will see this as diff computer but they have their own activated keys and H/D's installed

SO. my basic question was. If comp A clapped out. could i swap the C drive to B comp as hardware is basically same? NO as the drive will not match as wasnt made on B computer Basically. Conflict and deactivate - Side note- i have done this on another computer where the key WASNT activated and it worked fine, just a bit unstable in compatibility but enough to test sound, video ect Temporarily.

SO Solution? without doing the Comp A whole migrate programs transfer program deal File and add that to Comp B's H/D.?

Question- IF i used Comp B to clone Computers A's C drive to a fresh drive THEN put that cloned fresh drive into comp B, would that "code" the clone drive to accept in Comp B with activation unaffected, or still only the clone would work back in Comp A ?
- Note DOES the C drive you are trying to clone HAVE to be plugged into the M/B and thus i couldnt do this anyway. Basically can i have Comp B's C drive running the computer and use a caddy and USB ports with Comp A C drive and a fresh drive to clone to? maybe not.
Possible you can only clone the drive you want to when its installed in its OWN computer not another one?

 

[ex_bubblehead]

i totally understand that in practice but HOW does it differentiate between a clone drive and another computers drive if BOTH are physically diff drives.

A statistically unique checksum is generated and recorded. No two systems will generate the same checksum. Anything beyond that was never revealed by Microsoft. This is all you need to know. And, at this point you are getting VERY close to stepping over a line that we don't allow to be stepped over here. Suffice to say that Windows knows when it is running on hardware different from that upon which it was originally activated.

 

[stuff and nonesense]

SO. my basic question was. If comp A clapped out. could i swap the C drive to B comp as hardware is basically same? NO as the drive will not match as wasnt made on B computer Basically. Conflict and deactivate - Side note- i have done this on another computer where the key WASNT activated and it worked fine, just a bit unstable in compatibility but enough to test sound, video ect Temporarily.

Correct, no. Activation will be lost

that "code" the clone drive to accept in Comp B with activation unaffected, or still only the clone would work back in Comp A ?

The clone drive would only work in the computer that the source drive came from. Clone computer A drive… work in A


What are the computer specs?

 

[Tim042]

Correct, no. Activation will be lost

that "code" the clone drive to accept in Comp B with activation unaffected, or still only the clone would work back in Comp A ?

The clone drive would only work in the computer that the source drive came from. Clone computer A drive… work in A


What are the computer specs?

Yeah, i already was betting on my idea wouldnt work and got 10/1 odds from vegas before your answer. I'm rich!..... Again!! hmm. I was simply looking for a quick emergency workaround without the tedious migrate programs and all the boxes you have to tick as i have couple hundred programs many of which wont transfer and program warns you of imcompatibility as well especially if you are moving from say win 7 to 10 on comp B. But i have had 95-99% success, just a lot time to do it.
The computer is a old Win 7 2012 Dell with I-7 CPU and tons ram and frankly never had a blue screen or failure booting. book says it "Comm grade" and i have a few of them so great to hot swap out but i always knew likely wouldnt work directly when the other computer has a active key.

Also i wonder........... if i tried this move to Comp B if it DIDNT have a key BUT then used say a unused win 7 key and try to activate Comp B? Would the its still not work as the M/B and Drive dont match eventhough the servers dont already have Hardware details saved on them as comp b was never activated yet?

 

[stuff and nonesense]

i totally understand that in practice but HOW does it differentiate between a clone drive and another computers drive if BOTH are physically diff drives.

Windows doesn’t care about the drives used. Taking a boot drive (C) and cloning it to a Samsung Drive is done straightforwardly with the free Samsung software. Putting the clone drive into the source computer was/is effectively no change.

Components in a pc are fingerprinted by windows when the OS is installed. If I recall correctly different components have different “weightings” so you can change a GPU and not need to authorise again after a GPU change but change too many components at the same time.. if the weighted values exceed a threshold then the OS will need to be reauthorised.
The anecdotal suggestion was to change pci cards one at a time and reboot between changes!
This was the windows XP authorisation description I saw a number of years ago.

The motherboard had the greatest weighting as changing the motherboard was effectively putting the OS drive into a new computer.

 

[stuff and nonesense]

“Also i wonder........... if i tried this move to Comp B if it DIDNT have a key BUT then used say a unused win 7 key and try to activate Comp B? Would the its still not work as the M/B and Drive dont match eventhough the servers dont already have Hardware details saved on them as comp b was never activated yet?”

I’m assuming you mean clone the drive from comp A and install it into comp B.

There is a possibility that the drive will migrate and entering the key as MS have turned of the Win 7 activation servers a phone call will be needed… and MS may still not authorise the software. It is no longer supported.

Authorising would generate a new fingerprint for that set of hardware. You would be hoping that MS allowed the authorisation, its out of support.

I have moved boot drives across AMD to AMD, different processor generations, motherboard generations and I have moved drives across Intel to AMD, I have had no problems with regard to hardware and drivers but I consider myself lucky. Your mileage may vary.

The first thing I do on swapping is install motherboard drivers, then GPU drivers then check windows update.. I have always been prepared to reinstall Windows.

 

[Tim042]

“Also i wonder........... if i tried this move to Comp B if it DIDNT have a key BUT then used say a unused win 7 key and try to activate Comp B? Would the its still not work as the M/B and Drive dont match eventhough the servers dont already have Hardware details saved on them as comp b was never activated yet?”

I’m assuming you mean clone the drive from comp A and install it into comp B.

There is a possibility that the drive will migrate and entering the key, so long as MS are still running the servers you will be able to authorise. If not a phone call may be needed… and MS may still not authorise the software. It is no longer supported.

Authorising would generate a new fingerprint for that set of hardware. You would be hoping that MS allowed the authorisation, its out of support.

I have moved boot drives across AMD to AMD, different processor generations, motherboard generations and I have moved drives across Intel to AMD, I have had no problems with regard to hardware and drivers but I consider myself lucky. Your mileage may vary.

The first thing I do on swapping is install motherboard drivers, then GPU drivers then check windows update.. I have always been prepared to reinstall Windows.

Yes you bring up some important points and tips. If i was to try to swap A To B with out a key on B, I would turn windows update off and run all the drivers ect till the computer settled down and then turn on windows update and see if it installs even if MS claims the 7 servers wont work. A while back i phoned MS and told her i just installed Win 7 and it did hundreds of updates and she was surprised, but maybe today not anymore work?. Problem is if the servers CANT activate, then the clock in windows OS will run out of time and you get that pop up saying "windows is not activated" and half the features dont work. So MS have done a good job making sure if you get a unactivated win 7 computer, you cant really use it. You said you done swaps like i asking about to already keyed computers and had no problems? but making the A drive as updated as possible on b and hope the new key would see the A drive as belonging to B and B's M/B? and activate? assuming the servers still can of course.
Back to start of what i said on this reply- If i did all the updates ect, THEN if it wouldnt win 7 activate, maybe do a in place upgrade to Win 10 and use the 7 key free upgrade and maybe.... it would read the M/B and foreign A drive and accept it as hardware fingerprint and ok win 10 and activate? If 7 wont anymore, might have to try Win 10? what do you think of this idea S & N?
I "believe" even if you rang MS to Authorize for 7, they wouldnt as they were very frosty and wouldnt even answer questions i had so days of them giving you a swap key ect to use for 7 is very likely gone. Your advice to change ONE thing at a time and restart is safer as the "number" is a close secret and i remember changing CPU's and one time i got a "click here to reactivate" box and that was it , all other times changing anything but the M/B didnt seem to cause a problem.

 

[stuff and nonesense]

The Windows 7 licence can’t be upgraded to a Windows license 10 anymore…. You would need to acquire a Win 10 license. They have you over a barrel now.

 

[USAFRet]

The more I read this, the more I uncover incorrect assumptions and underlying problems.

Desired basic concept: If System A dies, remove the drive and put it in System B. Proceed on with your day.

1. How many people have a whole identical PC just sitting around? I know I don't. And I wager I have more systems within arms reach than most.

2. If the systems are identical, it will likely boot up. But the OS Activation will fail in System B.

3. If the systems are NOT identical, Windows 7 is unlikely to boot. And if it does, there will be operational issues. Activation again fails.

4. If System B already has its own OS, why not simply install (NOT transfer) the desired applications.

5. The personal data. There should be multiple copies of this anyway. Some readily accessible, maybe another copy offsite. You should not have to move the single physical drive from A to B in order to keep working on that important spreadsheet. If my current main system were to die right now, I could recover ALL of my data, or even the OS drive, in exactly the state it was at 2-3-4 AM this morning.

 

[stuff and nonesense]

The more I read this, the more I uncover incorrect assumptions and underlying problems.

Desired basic concept: If System A dies, remove the drive and put it in System B. Proceed on with your day.

1. How many people have a whole identical PC just sitting around? I know I don't. And I wager I have more systems within arms reach than most.

2. If the systems are identical, it will likely boot up. But the OS Activation will fail in System B.

3. If the systems are NOT identical, Windows 7 is unlikely to boot. And if it does, there will be operational issues. Activation again fails.

4. If System B already has its own OS, why not simply install (NOT transfer) the desired applications.

5. The personal data. There should be multiple copies of this anyway. Some readily accessible, maybe another copy offsite. You should not have to move the single physical drive from A to B in order to keep working on that important spreadsheet. If my current main system were to die right now, I could recover ALL of my data, or even the OS drive, in exactly the state it was at 2-3-4 AM this morning.

I’ve been looking at it from a position of redundancy.
Clone the original drives and get the data safe.

Transferring a drive to a new pc isn’t ideal. You may have had bad experiences, I’ve been lucky. I don’t have identical hardware but I have had no problems across architectures. Only once have I had to call MS to reactivate.

Windows has handled dissimilar systems, and across amd/intel.

User was attempting to avoid reinstalation.

Cloning the drives for redundancy and preservation of the licenses imho is the simplest method. Clone drive A for PC A, B for B etc.

The ideal if possible is a fresh install when transferring drives, though window doesn’t handle the action as disastrously as you suggest.

 

[USAFRet]

I’ve been looking at it from a position of redundancy.
Clone the original drives and get the data safe.

Transferring a drive to a new pc isn’t ideal. You may have had bad experiences, I’ve been lucky. I don’t have identical hardware but I have had no problems across architectures. Only once have I had to call MS to reactivate.

Windows has handled dissimilar systems, and across amd/intel.

User was attempting to avoid reinstalation.

Cloning the drives for redundancy and preservation of the licenses imho is the simplest method. Clone drive A for PC A, B for B etc.

The ideal if possible is a fresh install when transferring drives, though window doesn’t handle the action as disastrously as you suggest.

And I have had it absolutely fail moving a drive or clone between systems. ANd I've also had it work.
Sometimes ti works, sometimes it fails. Sometimes it works...mostly.

And with Win 7 and earlier...much less probability of success.

 

[BFG-9000]

This is a more complicated question than first appears, and the suggestion I have is to clone one of the drives and just try it... if you have two identical prebuilt PCs.

See, Windows XP and Windows 7 and all the way up to Windows Server 2025 can use SLIC table offline activation, no internet required (Windows 8 and later do NOT do this). So if you have say two DELL, HP or Lenovo OEM machines that each came with Windows 7, they will each have the correct SLIC table in the BIOS so if you use the OEM modified install disk there will be an unlimited number of installs that you can do, each of which would be immediately activated. A Windows installation created from such a disc with OEM certificate and generic OEM product key might be moved to another machine and find a compatible SLIC table in the new computer... and stay activated. We've run across people in these forums who routinely swapped drives between similar but not identical laptops and it worked fine.

But only large OEMs pre-activated Windows this way. If your Windows was not installed like this, then for example WPA of retail versions of Windows XP look at 10 things, some of which are more important than others:

1. - The display adapter - the video/graphics card
2. - SCSI adapter - if present
3. - The IDE controller (the built-in IDE or SATA hard drive controller)
4. - Network adapter (NIC) and especially its MAC Address
5. - RAM - amount
6. - The processor's type - the make and model of processor(s) from CPUID instruction
7. - The processor's serial number [not all processors have serial numbers, and some that do allow it to be disabled in BIOS]*
8. - The hard drive device
9. - The hard drive's Volume Serial Number (VSN)
10. - The make and model(s) of optical CD/DVD drive(s) installed.
The make and version of the BIOS doesn't count at all.
* it may sound quaint, but in 1999 the outrage from the privacy implications of having a software-accessible serial number on the Pentium III was so severe that it led to most board manufacturers offering a BIOS option to disable it. Think about that when they tell you the Trusted Platform Module required for Windows 11 is for "platform integrity" and not so they can identify you to sell your habits and interests to advertisers, That's just coincidental.

Now you may look at this list and think that you've upgraded most of these things before without triggering online reactivation (though back then you'd get one free online reactivation request granted every 4 months up to 10 times, after which you'd have to talk to someone on the phone. But now of course you can't legitimately reactivate online or by phone at any price) and it's true that you can gradually replace almost all of them except one, and that's the MAC address. If that's removed (whether by lightning strike or by simply disabling the onboard one in the BIOS) then Windows deactivates itself immediately on the next boot (and you didn't get the 120 day grace period either, it just wouldn't login without online activation... which was sure difficult without a NIC. Not even once to install another NIC).

I once had a run of Shuttle motherboards where the built-in onboard gigabit cards all had the same MAC address (thanks Shuttle for motherboards that couldn't easily be used on the same network by default) and I could swap Windows installations among them because of this, without triggering a deactivation.
So if you just happen to have installed Windows while the onboard was disabled and an add-in NIC was installed, try moving the NIC at the same time as the drive.

 

[Tim042]

This is a more complicated question than first appears, and the suggestion I have is to clone one of the drives and just try it... if you have two identical prebuilt PCs.

See, Windows XP and Windows 7 and all the way up to Windows Server 2025 can use SLIC table offline activation, no internet required (Windows 8 and later do NOT do this). So if you have say two DELL, HP or Lenovo OEM machines that each came with Windows 7, they will each have the correct SLIC table in the BIOS so if you use the OEM modified install disk there will be an unlimited number of installs that you can do, each of which would be immediately activated. A Windows installation created from such a disc with OEM certificate and generic OEM product key might be moved to another machine and find a compatible SLIC table in the new computer... and stay activated. We've run across people in these forums who routinely swapped drives between similar but not identical laptops and it worked fine.

But only large OEMs pre-activated Windows this way. If your Windows was not installed like this, then for example WPA of retail versions of Windows XP look at 10 things, some of which are more important than others:

1. - The display adapter - the video/graphics card
2. - SCSI adapter - if present
3. - The IDE controller (the built-in IDE or SATA hard drive controller)
4. - Network adapter (NIC) and especially its MAC Address
5. - RAM - amount
6. - The processor's type - the make and model of processor(s) from CPUID instruction
7. - The processor's serial number [not all processors have serial numbers, and some that do allow it to be disabled in BIOS]*
8. - The hard drive device
9. - The hard drive's Volume Serial Number (VSN)
10. - The make and model(s) of optical CD/DVD drive(s) installed.
The make and version of the BIOS doesn't count at all.
* it may sound quaint, but in 1999 the outrage from the privacy implications of having a software-accessible serial number on the Pentium III was so severe that it led to most board manufacturers offering a BIOS option to disable it. Think about that when they tell you the Trusted Platform Module required for Windows 11 is for "platform integrity" and not so they can identify you to sell your habits and interests to advertisers, That's just coincidental.

Now you may look at this list and think that you've upgraded most of these things before without triggering online reactivation (though back then you'd get one free online reactivation request granted every 4 months up to 10 times, after which you'd have to talk to someone on the phone. But now of course you can't legitimately reactivate online or by phone at any price) and it's true that you can gradually replace almost all of them except one, and that's the MAC address. If that's removed (whether by lightning strike or by simply disabling the onboard one in the BIOS) then Windows deactivates itself immediately on the next boot (and you didn't get the 120 day grace period either, it just wouldn't login without online activation... which was sure difficult without a NIC. Not even once to install another NIC).

I once had a run of Shuttle motherboards where the built-in onboard gigabit cards all had the same MAC address (thanks Shuttle for motherboards that couldn't easily be used on the same network by default) and I could swap Windows installations among them because of this, without triggering a deactivation.
So if you just happen to have installed Windows while the onboard was disabled and an add-in NIC was installed, try moving the NIC at the same time as the drive.

Thanks BFG for that exhaustive (thanks to MS) explanation and i will absorb it all later to fully take it in. Learning German Grammar is easier than this!! haha

The Win 7 servers seem to be "Kaput" now as i havnt tried any installs ect for a couple years, so what happens if IYO,

1 I try to do fresh install and use a unused win 7 key to try activate?

2 Try to use a Win 7 key to activate win 10 after do win 10 install? (win 7 key was not yet used to get win 10)

3 Most important... IF i already have a win 7 computer that WAS activated and i do a fresh install and need to put in key again, will it activate? or is this done from the Registry automatically so servers not needed?

4 I assume that once a Win 7 key and computer is running happily, you can make boot clones ok and do a fresh install and put key back in and it will be ok? i might have already asked that.

Not sure if having OEM or retail would effect your 4 answers? please explain if needed... Thanks