Actually posting this question for a family member who's computer is screwing up.....It appears that there is no signal coming from the video card. When the computer is turned on, there is no screen at all, just all black. When the monitor is unplugged from the computer, it gives that "no signal" message on the monitor. I also hooked the monitor up to my computer and it worked fine. So that eliminates any problem with the monitor itself. The only thing I can think of is a bad video card. Does anybody have any advice what to do? Should I just buy a new video card?

Computer is running XP, I think it's a P4 with 512 memory

Are you certain it is a card, and not integrated video? If a card it may need to be reseated. If both a card and integrated, try using both. If a dualhead card ty the other port, if compatible.

If they don't get the initial POST beep, then the system is dead and there will be no display.

By inital POST beep, are you referring to that beep when you first turn the system on?

Yes, that would be the beep he's referencing.

If you do get something on the screen until Windows boots, then the PC is probably just sending a resolution/refresh the monitor can't handle.

There is no beep when it first starts up, and nothing at all on the monitor shows up. Strange though, the computer I'm on right now doesn't make a beep when it starts and is running fine.

Older MBoards didn't have an integrated beeper, so the MBoard needed to be connected to a case speaker. Not all cases had speakers. So sometimes if no external speakers are connected and powered during startup, you won't get the POST beep.

This computer is newer and it did beep on startup. So since there's no beep what would that mean? What part would I have to replace to get it going again?

Could be most any component but the most likely candidate would be the power supply. With the case opened try starting the computer and opserve any signs of life. Lights on MBoard, fans moving, etc.

I assumme you have checked to verify there is power at the wall socket?

Open the case, discharge any static from your body, and then check all cards, cables, memory for secure connections. Sometimes things can work loose.