OEM licenses can be kind of funny. They aren’t portable, though I would’ve thought that the motherboard was replaced by a motherboard by the same OEM, etc. and should’ve qualified to use that OEM’s license.
It does, or at least it used to. Back during the Vista days my copy of Windows failed to activate after I replaced the motherboard, but Microsoft support was happy to help me when I explained that it was the same computer with new parts in it.