I have a Mirrored Door dual 1 ghz G4. When I went to wake it this morning, I usually only put it to sleep, I noticed it had powered down. I pressed the power button and it did nothing. I then changed the power cord and when I plugged it back in the fans started blowing but that's all that happened. I don't know if you've ever heard a MD with all the fans going (wind tunnel) but that's what happens if I plug in the power cord now. Could it be related to the power supply? Fans all seem to work fine.