Chosen Solution

Replaced the power supply. No drives, no RAM, no pci cards, no video cards, no DVD reader/writer. I plug in the power cord, and it powers up, fans spin normal, front LED is solid white. Nothing else. Battery checks ~3.0V. Not sure what to do. Unplugged it several times, drained the power supply with ~10s front boot button pressed. Sat overnight unplugged several times. LEDs showing nothing. It’s in my garage, around 5°C, so it’s not overheating instantly on power-up. Any insight what to do? I’m at a loss. Cheers

Well, got her working. Moved RAM modules around, and flipped RAM Risers up and down several times. The ATI graphics card was not good. Replaced it with an NVIDIA GeForce 8800, then added another one (I need 4 displays working again). I’m running through some Hardware Tests which take about 70 minutes for 6 individual 1 GB RAM sticks, for extended testing. I tried with NO RAM, and it simply wasn’t working. This was suggested elsewhere and was completely bad advice.