You could look in device manager for hardware with a yellow ! on it.
Start > Run > Type devmgmt.msc and hit enter
If anything has a yellow ! icon, there's something wrong. Most likely a driver issue.
C2D E6600 | 4GB DDR2-800 | 9800GTX+ | Asus P5B-E | 150GB Raptor | 320GB 7200.10 | 750W Xigmatek PSU