BlitzXFire :
So I'm upgrading my PC and giving some of my old parts to someone, my question is if I licensed a copy of Win8 OEM to the old mobo do I have to transfer the license to my new mobo before I give the old mobo to someone?
As long as your old Mobo is used in a system with a separately licensed OS you will then comply with the One System One Licence rule. You will probably have to activate your new rig by telephone to M'soft, and will be asked 'On how many PCs will the Product be used' answer - one, no problem...