get the "Please check signal cable" after a few shutdown/power-ups. I swapped the monitor and video card, (both work fine on other PCs) still the error. I can remove the video card, and reinsert it back in, powerup the PC and its fine for another couple of times. Haven't tried the power supply yet, hate to invest the money if that won't fix it. Is there anything else to try first? I tried different PCI slots(PCI video card) and still the error too.

Do you get the single POST beep when it fails?

Nope, didn't hear anything, but the fan on the power supply works. and reseating the video card works every time for a little bit. I tried every PCI slot I have and same thing.

If you don't get a beep, that means the system is not starting up and you will not get a display. It's a hardware problem. Probably a poor connection or defective component somewhere on the motherboard, but it could be a problem with anything connected to the motherboard. I suggest reseating the motherboard power connector first.

reseated the power connector, (its an AT supply so its been here for a while) still same thing. I don't think the motherboard is fried because it does work after the video is reseated. Do you mean that a memory chip could have gone bad and thats why I get the message, or the cd-rom drive is bad and that could be why too? or what about that little battery on the motherboard?

You usually get error beeps for a RAM or video card problem. A defective battery will usually cause a cmos checksum error or the clock losing time, but not a system failure. It's possible for a defective cdrom drive to cause the problem. Like I said earlier, it could be an intermittent problem with anything connected to the motherboard stopping it from working. But it really sounds like you have a flaky connection on the motherboard and reinserting the video card is jiggling the connection. This connection could even be inside one of the chips on the board. I hesitate to give any more troubleshooting advice, because it might make matters worse.

Well, thanks for your help. At this point I really have no choice than to go ahead and replace the power supply because its still cheaper than replacing a motherboard. I wish I could try it on another computer but like I said earlier its an AT not an ATX. All I know is that motherboards dont usually behave like this. I've had it in the past when one PCI slot was the problem, or I even reseated the memory and that worked, or adjusted the screen resolution and that worked. The cd-rom is working fine, along with the floppy and hard drive. I guess I know what I need to try next (power supply). Thanks for your help, I appreciate it.