Hey guess what.....
We need to know what was the old motherboard....
And which is the new one your going to get....
If your going from a Intel Chipset to a Intel Chipset, it will be easy.
If your going from Nvidia chipset to Intel Chipset then its different...
When you post questions in future it will speed up the process when you let us know the complete story.....
Cheers
HB
ps
If your going from Intel to Intel...
Uninstall the old Intel chipset drivers, and Audio, reboot then install new Intel chipset, then the sound, video card drivers would be worth a refresh too.
secondly you may have to reactivate windows, easy to do on the phone if it dont work by the internet...
Good Luck