This is an 8 year old PC I built. I was not at the computer when it died. I was using it through a remote connection. The connection stopped, so I went to the location of the computer and found that it would not turn on. The electric had not gone off, since there was a clock plugged into the same outlet that did not need to be reset. There were no storms or any other indication of an electrical surge. The building it was in, was empty with nothing electrical running except things like clocks. When I hit the power button - zero response. I took it home with me to examine and after checking all the basics - power cord, cable connections, properly seated peripherals, there still was no response. No lights, no fans turning on - nothing. I changed out the CMOS battery for a new one - didn't help. I decided it was a good chance of a bad power supply and I had a new one for backup. I put that in, and no response. Now, I'm getting worried and suspect maybe the motherboard. I figured the on/off switch shouldn't be the problem since it died while being used. However, even with a MB problem, I would have expected something less dramatic than total death. I don't want to experiment with replacing that, if it might be something else. I took the graphics card out, checked RAM seating. I even disconnected all the drives just to see if I could get it to turn on. The only response I can get, is when I unplug the computer and then hit the on/off switch multiple times to drain any power from the system. When I plug it back in and hit the on/off switch, I get very momentary flash of the green light next to the on/off switch. It's just an instant flash and easy to miss if you aren't looking for it. To get the flash to happen again, I have to go through the same procedure of unplugging and multiple presses of the on/off switch, before retrying. I've been able to diagnose and repair a lot of computer problems over the years, but this one has me stymied. Any ideas?