Unable to activate Win7 after re-installing from 32-bit to 64-bit

[Cacodemon]

This actually isn't my own problem, but someone I'm trying to help. Recently they re-installed Windows 7 64-bit Ultimate from an Ultimate 32-bit installation, both the same key/copy. After installing 64-bit Ultimate, Microsoft says their CD key is blocked and are unable to activate. They attempted to revert to 32-bit from frustration, but now 32-bit is blocked, as well. So both 32 and 64 are blocked.

For years they used 32-bit. During those years, they changed their motherboard and hard drive. They used the 32-bit version on both motherboards and different hard drives without error. Their license is a retail version, not an OEM. But, is it possible Microsoft has the CD key tagged to the old 32-bit version and sees the new 64-bit installation as invalid? In other words, is this potentially an error on Microsoft's end?

Addendum: We know their license is retail because their initial purchase of Win7 Ultimate came with a builder's kit key. After a year passed, they were able to obtain a legitimate retail license from Microsoft after explaining and proving their situation with the initial vendor.

 

[NoelDP]

Please follow this tutorial and post an MGADiag report - then we can see what the problem is.

http://www.sevenforums.com/windows-updates-activation/234159-windows-genuine-activation-issue-posting-instructions.html

Ignore errors produced when clicking on the Copy button - they simply mean that the tool could not create the backup files for some reason. The data is still copied to the clipboard for pasting to your response.

Please also state the Version and Edition of Windows quoted on your COA sticker (if you have one) on the case of your machine (or inside the battery compartment), but do NOT quote the Key on the sticker!
http://www.microsoft.com/en-us/howtotell/Hardware.aspx