NagoyaHammer.com

Hey,
Perhaps one of you can help me.
When I was using my pc yesterday morning it shut down with no warning. When I pressed the on button, nothing happened.
I opened the case and checked for loose wires, but couldnt find anything. I tried switching the power leads to no avail and after testing it (ie pressing the on switch several times) decided to take my Pc to the shop at the first opportunity.
When I came home tonight, I figured that I would try it one more time. Everything worked fine first time, but nothing had changed since yesterday.
I'm kind of stumped. Any thoughts?

I'm no expert, but I'll take a few wild stabs at it:

1) It overheated. Perhaps dust is interfering with the cooling system.
2) Some issue with the outlet.
3) Virus
4) It got scared you might try to watch Star Wars Episode I and went into hibernation until the coast was clear.

I vote for option 1 or possibly a loose connection somewhere that you didnt notice. Seems mechanical, rather than electronic or software related, I reckon.

I had a similar problem last month; my 4-year-old PC had shut down on its own overnight and in the morning wouldn't finish the boot cycle, shutting down instead.
The problem? Dust. I thought I was cleaning it often enough but apparently I wasn't, so if the Eiden guy was to be believed my Power supply unit (the box with the fan at the rear of the case) and my videocard were both cooked. The good news? 30,000JPY later the problem was solved (had them double the memory to 4gb while they were at it, but that was only about 20% of the total cost).
I hope in your case it's just the PSU, since that isn't that expensive a fix, but in the future get some compressed air and clean your internal components once a month or so, esp. if you're like me and keep the beast on 24/7.