My computer powers on. The green light stays on for about fifteen seconds then turns off. At the same time the monitor says 'no signal found' and doesn't show what the computer is doing. None of the keyboard lights stay lit, but the usb mouse light for the remote mouse and external hard drives will light up. I disconnected everything except keyboard, mouse and monitor and still nothing. I swapped out the video card also. The computer had worked fine until I started to download Service Pack 3. Any help would be appreciated.
Thanks
Vince
