Installed a system image over my OS and now I need the product key, can I get it back from the previous OS?

[HyperCraggles]

Ok, so to go into more detail I just built my PC and needed to boot it up with windows. So, I got my USB installation media and set it up to install it. I'm at the setup screen and it asks for my product code, which I readily type in and continue to install windows 8.1. I set up a new Microsoft email for this PC and fully load windows. Now here's where the problem starts. I want to have everything from my old PC and put into onto my new PC. I thought first of just copying over system files etc. to a HDD but then I read about using a system image restore to copy EVERYTHING to the new PC, inclusive of settings, installations etc. So make an image and do the processes to load it onto the new PC. I was aware that it would overwrite my old OS and I was fine with that, but I also thought that I would be able to use the same product key for the download. Unfortunately, this was not the case and the error that appears for the activation of my windows is "Sorry, this windows product key is not valid for this edition" Into more details, it says I have already used the key once.

My question being, is there a way to make my product code valid? (seeing how its not one the PC anymore), if I were to do a clean install of windows 8.1 again, would my product key work again? Does making a new account affect the product keys in any way? (my new PC is running my old account as it is a system image), will Microsoft do anything to help if a contact them, and if I do a clean install again and use my product code works, is it just as easy to copy and paste the hard drive from the old PC to the new PC?

Sorry if its butthurtfully long, but any help would be fantastic!

 

[USAFRet]

I want to have everything from my old PC and put into onto my new PC

That was the first problem

but then I read about using a system image restore to copy EVERYTHING to the new PC, inclusive of settings, installations etc.

That was the second problem

Where did the original install come from? Was it a preinstalled OEM? Or something else?
Where did the Windows 8.1 install come from? Something you bought?

If it is something you bought separately, starting again and reinstalling is no problem.
But you can't somehow port all your previous applications, etc onto the new 8.1 install. You need to reinstall all the applications again with the new OS.

 

[HyperCraggles]

I want to have everything from my old PC and put into onto my new PC

That was the first problem

but then I read about using a system image restore to copy EVERYTHING to the new PC, inclusive of settings, installations etc.

That was the second problem

Where did the original install come from? Was it a preinstalled OEM? Or something else?
Where did the Windows 8.1 install come from? Something you bought?

If it is something you bought separately, starting again and reinstalling is no problem.
But you can't somehow port all your previous applications, etc onto the new 8.1 install. You need to reinstall all the applications again with the new OS.

The original was a preinstalled OEM, the new one was bought directly from the microsoft store. When I installed windows onto the new PC, I set up everything, like it was fully operational (able to use internet etc.), and I just used a system image over that. So if I were to do a clean install again, could I use that same product key even though it is apparently invalid?

 

[USAFRet]

I want to have everything from my old PC and put into onto my new PC

That was the first problem

but then I read about using a system image restore to copy EVERYTHING to the new PC, inclusive of settings, installations etc.

That was the second problem

Where did the original install come from? Was it a preinstalled OEM? Or something else?
Where did the Windows 8.1 install come from? Something you bought?

If it is something you bought separately, starting again and reinstalling is no problem.
But you can't somehow port all your previous applications, etc onto the new 8.1 install. You need to reinstall all the applications again with the new OS.

The original was a preinstalled OEM, the new one was bought directly from the microsoft store. When I installed windows onto the new PC, I set up everything, like it was fully operational (able to use internet etc.), and I just used a system image over that. So if I were to do a clean install again, could I use that same product key even though it is apparently invalid?

Yes, you can use the key you bought, in conjunction with the fresh install again. You may have to activate via phone.
You can't use the new key with the old OEM image.