installing W7 OEM?

[Radec]

My PC right now has an unactivated version of windows 8 pro running.
If I were to buy an OEM version of 7, would I be ok to install that?
The PC is custom built.

 

[AzZ]

Yes. OEM license will be tied to your motherboard though so if you change it in the future you will have to call up Microsoft to re-activate it.