Check windows device manager for any marks next to a device, which means the device driver isn't loading or there's a conflict somewhere. Uninstall the device. You may need a windows cd to replace a driver when you reboot. I would also go into the bios by pressing the "del" key just before the post screen and set the boot order to cd>hardrive, save and exit. The replacement board may have an updated bios that has changed a setting which could also be causing your issue, and it wouldn't hurt to replace the motherboard battery, usually the round button battery cr2032, which you can buy at electronics shops or even some walmarts for $2-3. Frys sells them in 4 packs for about $5.