Hi,
So we can kind of get an overview of a few things, download and run this free program and post it for us. It does a great job of monitoring some things:
SensorView Pro (Free to try for like 21 days – Is excellent)
http://www.stvsoft.com/download.php?id=122
While it may very well be a driver, it may be something else that doesn't let a proper driver function properly.
Quite honestly, you may also have to begin to look at the power supply in this instance. The program might help us in that area too. While you are at it, look on the side of your power supply and tell me how many amps are listed on the +12 volt rail.
Post back with results.