Could be that you just got a bad card. I would return it and try again, if you have already done a clean install of the driver software. By the way, what graphics card are we talking about here. Plus, you aren't crossfired are you? I have heard that this problem happens a lot when you crossfire graphics cards. Also, try pulling the card out and just going through the area with a can of compressed air. Sometimes dust trapped in the PCI port will do this to you.