Qwazil...when the operating system was first installed it searched out all of the drivers it would need and recognized the chip set, when you installed the other motherboard with its different chip set you basically confused the heck out of it. When I did that my OS very quickly got worse and worse to the point it wouldn't open.
If you have the installation disc and product code I would suggest using a utility like [url=http://www.killdisk.com/]Wipe Drive[/url] and do a fresh installation. After you download the program you will need to make a CD of it as you computer will boot from it. This means that you will need to make sure that the CD-ROM is the first device in the boot order.