I have a geforce G100 video card that i bought with my computer about a year ago. It was working fine until a few weeks ago. The computer wouldnt start up. It would start and immediately shut down. In my investigating, the computer works when i just use the on-board video without the g100 installed on the mb. I am completely baffeled as to what the problem can be. The card and the mb look to have no burned out circuits.