Hey, I have a dual g5 2ghz with a 23" HD Cinema Display. Up until two days ago everything was working fine. Now I do not get any video feed on the display at all. The light for power is on and I can turn the computer on and put it to sleep using the button on the screen, however nothing shows up. The computer is running because I can eject the optical drive. Does anyone have any suggestions as to how I can start to troubleshoot this?