No video signal - bad mobo or psu?

System specs - P4 3.0ghz socket 775, Gigabyte GA-945GCMX-S2, 2xPatriot 2gb pc2 5300, nVidia 7300le pci-express, Cooler Master RP-500-pcar 500wt psu.

Problem - I was given the system knowing that it was failing. Here is what happens. When I boot the computer, I do not get a video signal but parts of the computer do power up. I used a known working LCD monitor that uses dvi and analog connections. HSF spins, video card fan spins, power supply fan spins, cpu gets warm (read in a thread here that suggested to use that as a possible check for cpu operation), northbridge chip and RAM also get warm, case fan that utilizes a 4 pin molex spins but a dvd burner that uses sata power does not spin (do not have a way of checking this - only power supply with sata connection is this one.) This is why I believe it is the power supply that is bad but it could be a dead dvd burner too.

Diagnosing -
1. I removed everything from the mobo.
2. Connected the 24 pin power connector and the other 4pin 12v connector (?) from psu to mobo and powered up the system. I get the beep codes for memory error. Installed either one of the two chips and it's fine.
3. With one of the memory chips in, I connect monitor to the on-board graphics adapter and do not get a video signal (monitor says to check cable no signal.) Did get a "monitor or display card error once" with one of the memory chips installed. Wanting to check the memory chip, I removed everything checked it by itself and did not get beep code. Rotated the chips to get every possible combination but no joy. This is why I think it is a bad mobo.
4. Installed the nvidia card and connected the monitor via dvi and analog but still did not get a video signal.
5. Removed the video card and monitor and I attached the sata powered dvd burner and it did not operate (would not open.)

I also tried resetting the cmos and the power button trick described in this forum (remove cord and hold down the power switch for 30 secs) without any success.


The owner that gave me the computer told me that he replaced the psu because it had a bad fan. This one sounds like it has a bad fan as well. It kind of has a faint smell of something burnt inside but it is faint.

Are there any other test I can do to eliminate the mobo, cpu or video card from being the problem? My other computers are socket 478 and the power supplies do not have the connectors I need to swap and try. I do have a sata hd to try but figured I need to get the video figured out first. Any help is appreciated.