Windows – How to tell if a Windows 8.1 Product Keys is an OEM key

According to Microsoft, an Windows 8 Key provided from am OEM is not transferrable:

Q: My customer bought a new PC and wants to move the OEM software from the old PC to the new one. Can't users do whatever they want with their software?

A: No, the OEM software is licensed with the computer system on which it was originally installed and is tied to that original machine. OEM licenses are single-use licenses that cannot be installed on more than one computer system, even if the original machine is no longer in use. The End User Software License Terms, which the end user must accept before using the software, state that the license may not be shared, transferred to, or used concurrently on different computers

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That's the legalese behind it. As far as technically, can you do it, Windows 8 OEM licenses seem to be tied to hardware hashes that include the motherboard:

manufacturers will be required to write a unique Windows product key -- which is associated with the hardware hash -- into the system's BIOS

Reference

So no, it would appear that even with the original OEM key and installation media, the key is bound to the hardware it is installed on.

You can upgrade to Windows 8.1 Pro and then use the WMC key after installation in the Add Features section.

The WMC keys you received last year work this year too.

Source: Personal experience