No image on screen?

[LBmtb]

So a friend of mine has a problem . . .

problem/symptoms:
Nothing shows up on his monitor. The monitor acts as it nothing is plugged into it (has a message saying 'monitor is working; check computer or cable'). He says it's been happening on and off for awhile and that sometimes moving the monitor's plug (back of computer) or restarting the computer will fix it.

tried:
I tried swapping out the monitor with two known working ones. No luck
Also tried swapping in a working video card (my own) but still no luck.

What could be causing this? The AGP slot? Something in the BIOS? Should I try to hunt down a PCI card to try?

Thanks!

 

[FlyingPenguin]

The monitor will display that message only if it's not receiving a signal from the video card.

What you haven't mentioned is whether or not you know for certain if the computer is actually running when this happens. It's possible for the power light to come on and the fans to spin, but for the mobo to fail to POST and thus no video signal.

If the mobo is not initializing and there's no beep errors then it could be a lot of things: bad memory, bad mobo, bad PSU.

Very hard to say without more info.

First thing I would do is connect another monitor to the computer next time this happens. If there's no signal on the 2nd monitor then you know the problem is with the computer.