Due to a faulty batch of board, my computer was recalled by the college.
Couldn't reactivate by internet, i had to ring Microsoft. No problems all they needed to know was the first block of digits on the code, and my license number. No more questions, and gave me a new activation code.
Yes it should activate OK, even an OEM version. If by any chance it does not do so automatically, then a quick call to Microsoft explaining the failure of motherboard and need to fit a new one will suffice. As TECHNODIMWIT says, quite painless.