Brought a new 7950 for my gaming rig. Took out my 560 after uninstalling all the drivers. Plugged in the new GFX card, put all the power cables in. Tun it back on. Card spins up and carrys on spinning but red VGA led appears on board. Have tried new bios, changing pci port, changing port that the monitor is plugged into. The computer works with my 560 still but not with the new 7950. Don't know what else to try. Help!!