I recently had to replace a few parts in my PC and thought that my Windows 10 activation through the Microsoft Account would be enough, however it wasn’t. In this article, I show how you can Activate Windows 10 with Windows 7 Key.
I went through Microsoft Support to get it reactivated, however as the original build was done through the free upgrade, the PC had changed too much to be considered the same computer for a reactivation. When speaking to the engineer they asked me for a Windows 7 key since the original computer was upgraded. Luckily I had a key available.
This command allows you to enter a Windows 7 Product Key to activate Windows 10.
It will work as long as it is a matching edition of Windows (e.g. Windows 7 Pro to Windows 10 Pro).
This has worked a couple of times for me now. See if it works for you.