I had a Windows 7 that was activated via BIOS mod and OEM product key. Don't even remember which OEM it was, that was years ago. When MS offered a free upgrade to Win10 I did that and migrated to "digital license". Recently I've upgraded my PC and replaced MB and CPU. The problem is that I cannot reactivate it again following "Hardware was changed" steps on MS website. Activation Wizard is giving me an error code 0xC004F211. I've even tried calling MS phone activation line, but that was an exercise in frustration, as the guy barely spoke English, and my German is s**t. He insisted that I have do find my old Win 7 product key and use it for activation. That sounds like complete bonkers, even if I had a genuine retail key. Do I have any "almost legit" ways to activate, or activation tools is my only option ?
Basically, the way Microsoft looks at it, your license (original OEM license for Windows 7) was tied to the computer that you purchased from Dell or HP or whomever. Once you changed the MB and CPU, that is no longer the same computer, at least not in their eyes. Therefore, the way they see it, you are no longer entitled to a free upgrade to Windows 10. I recommend you follow the advice from Enthusiast, in the post just above this. You will very seldom go wrong following advice from Enthusiast.