[djmcmath]

Ok, I'll assume you've done none of the basic troubleshooting -- please don't be offended if this is too basic:
1 - Check the power. Are you positive the outlet is live? Are you sure the cable is good all the way in to the power supply?
2 - Were there any warning signs? Anything abnormal last run? Feel the side of the case -- is anything warm (especially near the power supply, hopefully)?

Hmm ... hope some of the other heavies can weigh in. Dumb question -- is the screen on? Is it connected to the beige box correctly? Is the video card known good? Do any of the fans inside the case come on? Do any of the drives spin up at all?

Dan