I have a ati radeon hd5670 graphics card installed in my pc. I am using it since last 2 years. But now my cpu is not booting. Though the processor fans and the fan of the graphics card is spinning. I tried using my old nvidia 8400gs and the pc is working smoothly but whenever I am inserting hd5670 the cpu is not booting. Is my GPU faulty? plz help..........