Ever since Windows phoned home to be activated, the OS license has always been linked to the motherboard. You could replace the hard drive, change all the other hardware, and Windows remained activated although sometimes if too many parts were changed at once then a phone call to Microsoft was needed for re-activation, I only had to do this once.
But replace the motherboard and you are SOL and would need a new Windows 10 retail disk or download ($95 - $199). I have read an old computer could be deactivated and the new computer activated with a the same Windows retail disk but with the advent of the free upgrade to Windows 10 six years ago who knows where their old retail copy of Windows 7 with the activation code is?
Microsoft recently changed their policy and now even a motherboard swap keeps your license active. I just built a new music server and the only two items I reused from the old server was the SSD and Paul Pang Audiophile Grade USB card. The trick is to
first link your Microsoft Account to your Windows 10 Digital License, then back up your data.
Will it POST? That's always the question when you push the on-button the first time. Wires everywhere, no SSD, no DVD drive, just looking for the UEFI screen. A successful POST means the SSD can be plugged in and Windows 10 can be installed. I used the
Windows Media Creation Tool to put a fresh, updated version of Windows 10 on a USB flash drive. Plug in the flash drive and ethernet cable and configure UEFI to boot first from USB. I did a clean install which deleted everything on the SSD.
A few button clicks later I had an activated copy of Windows 10, the entire process was smooth and painless.
A detailed description of the entire process from linking to your Microsoft account to activation can be found here:
https://helpdeskgeek.com/windows-10/how-to-replace-a-motherboard-without-reinstalling-windows-10/Even though Windows would probably boot with the original Windows 10 on the SSD and attempt to repair itself you are still left with all the garbage, a clean install is best in the long run.
