BleepingComputer.com: Monitor Not Displaying Anything

Ok I have a computer where when I turn it on along with the monitor, the monitor says:

"The monitor is working fine, please check your video and cables" or something like that, with a red rectangle, a green rectangle and a blue rectangle moving up and down.

I've checked all the cables, they're all secure.

I've done this process many times so I'm sure I didn't plug things in wrong or anything.

I've tried using another computer and connecting the monitor to it, and it works fine.

So the problem seems to be the computer, which isn't sending the signal to the monitor or something? A friend of mine said the video card of the computer may have burned out. But I connected everything and it worked fine. After I switched it in like 5 minutes, I couldn't get it working anymore. Any suggestions?

Thanks

EDIT: OS is Windows 98 btw if it matters.

Start with your power supply. May sure the power cord is not loose. It sounds silly but the simplest things are often the cause. See if the fan is coming on inside the power supply. If this appears OK the next thing will be the video card.
I assume the drive (hard drive, cdrom, floppy) lights are coming on. Try removing and re-inserting the video card. If this makes no differences try the memory.
If the rest of the computer is not coming on check the ram. If you have two or more sticks remove all the ram. Insert 1 stick at a time in the first slot and try starting you computer. Slot 1 should be marked "0". Repeat this with all sticks and see if it will boot. If it does you have a bad ram.
Check the fan on the Processor. Is it stopped up with lent or dirt.
Try these things and post the results.

acklan, on Nov 11 2005, 10:48 PM, said:

if I remove and put back the video card in and do the same with ram and the same results happen, then does it mean it's the video card then?

i'm asking this beause i wanna get the theorertical stuff down before i head to my friend's place to actually try it.

thanks

The idea behind removing the cards and ram is it could become loose, or has poor contact. If you reinstall the ram and it works with some but not others then you have identified the problem. If it works after all were reinstall one or more may have been poorly seated.
If the processor fan is clogged it could indicate a faulty chip form lack of cooling.
Heat kills computer compontants.