Windows 8.1 CD to Install Windows 10

[icyanima]

I have a Windows 8.1 CD which i bought for my build few years ago but currently it has been upgraded to Windows 10 for free , and i wonder if im going to change my CPU , Motherboard , GPU , RAM and a new M.2 SSD , if i install Windows 8.1 with the CD will i be able to upgrade to Windows 10 again?

or do i just download Windows 10 and install with a Thumbdrive from Microsoft?

Do i have to buy a new CD Key for the Thumbdrive installed Windows 10?

 

[little_me]

that depends a lot on which version of windows you bought. If 8.1 was OEM, it was and still is tied to the hardware (pretty much mainboard only) and changing that will require a new license.
some have had luck with linking the license to their microsoft account where the hardware isn't no longer an issue.

Either way, you should try to tie the license with your microsoft/skype/outloook account and then install windows 10 from the downloadable media as you aimed to do.
If the linking to microsoft account didn't work and windows 8.1 license doesn't work (it should normally work for activating windows 10 unless hardware changes are an issue) then you might need to buy a new license.
so do this before hardware change:
http://www.windowscentral.com/how-re-activate-windows-10-after-hardware-change

 

[icyanima]

Thanks for the info , hopefully nothing will go wrong when i change my hardware. The new Windows 10 now sells in a USB Thumbdrive then a CD like the old days , didnt know that the licence locks on to your Microsoft Account.

 

[little_me]

you don't need to buy the win10 on usb if you already have a spare usb stick. (and don't need new license)
https://www.microsoft.com/en-us/software-download/windows10
has free download tool for windows 10 installation media, either to DVD or USB

 

[icyanima]

Yep , i installed one onto my spare usb stick just incase.