Here is the way to eliminate the possible faulty Motherboard:
Get your Windows install cd, pop it in, and boot from it. You use the mouse to navigate around the initial install with the basic kernel drivers that it installs to do the set up, During that annoying loading bar across the Black screen with the white loading bar at the bottom on first start up. You could go as far as to set up the whole windows on a small partition to be deleted after the test, but you should be able to determine if the mouse support issue is resolvable directly from the Pre-install areas of the Windows 7 CD.
Notice how the mouse is req, to determine why you stuck the CD and booted from it in the first place.http://www.youtube.com/watch?v=ZQGcj...eature=related
If the mouse does not move at this screen, that Mobo is a faulty.