Hi Aro69,
Yes, that should be fine. However, If the OEM CD came included with your computer (that was built by a large computer manufacturer) I am unsure if the software will even install without the old motherboard. But you can try.
Also, you may have problems entering the new Product Key into that OEM Vista install. I know in XP that Retail Product Keys would not work in OEM software. I am fairly sure that is still the case with Vista, but I haven't tried it first hand, so I am not 100% sure.
Darin Smith
WGA Forum Manager