I'm working on a Dell Dimension 5100 PC. It came with the Thermaltake 430W power supply, and my friend said she was working on it one day and it froze on her. She said it wouldn't power on at all. I swapped the power supply with mine (since I know it works - and it's 500W), and it booted up. Thinking this was the problem, I put it back together and tried to boot it up again. It wouldn't boot all all, no power, no diagnostics lights, just the green light on the motherboard. The odd thing is, if I take all of the RAM out the fans come on and the system beeps. It also will boot if I reset the CMOS jumper, but only once. If I turn it off again nothing happens.
Any idea what could be causing this?