(Re)Activation after identical motherboard replacement

(Re)Activation after identical motherboard replacement.
I had my 2008 era Dell motherboard fail but I was able to find a used MB matching my PC model, bios, cpu. I had saved my old boot drives for XP, 7Pro and 10Pro for that PC, and they all boot fine with the replacement MB. 7Pro and 10Pro no longer show as activated since 'almost identical' is apparently not enough. On 10P this shows as 0xC004F211, a HW change. I only ever had a local acct, so I can't use the Microsoft acct method to transfer the license if that was even an option.

It is my understanding that for W8 and newer, once anyone has activated the OS with a specific motherboard, the entitlement for the OS+MB pairing is forever recorded in a MS activation database. You or anyone else could move the MB to an entirely different box with blank drives and successfully clean install the paired OS and it would activate automatically. Is this true or does the process look at more than the MB? Can I assume that since 10P does not activate on my replacement MB, it must have come from a PC that never had 10P installed?

It seems like there should be a live-CD or boot utility that would query the MS activation database using the MB specifics and find out what OS entitlements already exist. If such a tool existed, then sellers of used systems without drives could still list such information. Instead you have to first install an OS and then hope the activation process finds a match. This process only says if a key is valid or blocked, and not the entitlement history of the MB.

If it is a hardware change, you could have difficulty if the activation was done with free upgrade from win7>win10.

One of my machines has been deactivated . It wasnt a hardware change but the os thought it was.

There have been numerous other people affected.

It is possible your second hand mobo might have had win10 HOME activated on it. Only way to find out is install HOME and see what happens.

The troubleshooter only says that it can't activate windows. It gives no details. If I hit "recently changed HW", it wants me to login to an account I don't have. In seems that I would have needed an existing MS acct setup before I replaced the HW, or a way to fix and boot the old MB, or a new license.

According to https://support.microsoft.com/en-us/...EBD=Windows_10 , to reactivate you need either a digital license or a product key. If you have lost any physical or "noted in a file" register of your product key, maybe you can recover the latter with NirSoft's ProduKey ProduKey - Recover lost product key (CD-Key) of Windows/MS-Office/SQL Server . It's not for sure, as your current Windows isn't activated now, although it was before.

Thinking back, when the PC was new it came with XP preinstalled. I later upgraded to 7P with a purchased key (prob OEM). I saved the email with that key. I briefly installed 10P during the free upgrade period but continued with 7P for years. Last year I reinstalled 10P fully expecting to have license or compatibility or performance issues on such old HW. To my surprise it installed fine, found the 10P entitlement, and ran just as well as it had under 7P. A month or two later it failed to boot which proved to be the motherboard. I don't know if the 10P install converted the 7P key to a new one, since I didn't think to use a key finder util when I could have. Even if it did, or I was able now to discover it from a disk image, it probably wouldn't get around the "changed HW" activation issue.

It turns out I must have created an MS acct at some point, but when I log in it only shows one of my other PCs and not the one I am working on.

I don't think this has to do with having or not an MS account. Although I don't know the exact terms of the 7P OEM? -> 10P free upgrade, if the 7P was OEM, likely the 10P was OEM too. With a retail license and some proof of purchase or property you could phone MS and get a solution. I had some technical difficulty when installing my for the time being recently purchased 10P, I can't recall it exactly, but in a "Win10 pro" folder of my data drive I have the following files (I think the 3 names were made or altered by me): MediaCreationTool21H2 (did not work).exe, MS assistance.txt, Win10_21H2_Spanish_x64.iso. The txt file has the following content:

Do you need help?
Call xxx xxx xxx (MS assistance number in my country)
Order number: xxxxxxxxxxxxxxxx

case number XXXXXXXXXXXXXXXXXXX

I suppose I saw the first 2 lines in a web, I phoned xxx xxx xxx, and they provided me with a case number and a solution after telling the order number and describing the issue.

Btw I have been able to d/l w/o issues and use successfully the MCT some few days ago to get an updated iso.