Unexplained Shutdown

Windows XP Home, Sp.3, All Updates

Sometimes after an hour or so, sometimes after several hours, and not always, my computer will inexplicably shut down. The screens are black, the mouse light is out and the keyboard and mouse have no effect. The fans are still running and the LED's behind the switch are on but the switch and boot switch are inoperative.

At this point the only thing to do is unplug the machine and then plug it back in. The power switch now works and the machine boots up normally with no message that says an unexplained shutdown occurred.

All the power functions having to do with the disks, hibernate, etc. are always on.

Can someone suggest an explanation?

Thank you.

 

Hi sdculp, Have you carried out any clean ups lately? Defrag > Clear Temp Files?

It doesn't sound like a Hard Drive failing but it wouldn't hurt to run the HD Brand Diagnostic tool. Neil.

 

Thanks for the response and your thoughts.

I’m pretty good at keeping the drive clean and there is plenty of room in the c drive. The system has run for the past 2 or so years and this problem has only occurred 3 times in the last couple of months. I located SeaTools for Windows and ran both the short and long diagnostics. I also cleaned out the dust bunnies but didn’t find anything significant.

The more I think about it, the more I think that the power/boot button and reboot buttons were inoperative is an important clue. If it was a Windows or disk problem, those buttons would still be operative, wouldn’t they? Although the fan was still operating, suppose that something caused one of the power supplies to trigger an electronic breaker and shut down. The only way to reset it would be to cycle the 110v. That’s what I did, and after that the power/reboot switch was operative and the system restarted as though nothing had happened.

The computer is a custom build and I don’t know how close to the limits the power supply is. I haven’t added any more power-using components. Breakers are basically thermal devices triggered by current or temperature. It was extremely hot this summer and the problem didn’t occur then.

What do you think about this idea? Maybe this is the wrong forum?

Thanks again.

 

I had a switch fail a few years ago and had to swap one from an old case as the aren't available as a part to purchase.
The power is switched on and off through the motherboard. The cable and connectors from the switch go to the connectors on the M/B - so between that connector block and the PSU - there are circuits through the M/B to the ATX connector.
There probably are, as you explained, breakers in the circuits to protect the board. A re-boot sounds like a wise 1st. option.
Glad to see you're back to normal again. Neil.

 

Hmmm. Your comment about the switch reminds me of a comment the tech made when he was building my computer a couple of years ago. Something about the switch was not quite right and it was built into the case and couldn't be replaced but he fixed it with epoxy and "it should be ok ".

If the switch was bad, one would think that punching it a few times would work, but there may be other things involved which require a power cycle to get things going again.

If this thing keeps happening and it gets too irritating to keep power cycling to get back on the air I think I will let the tech fix it. Looks like a mobo, switch or ps problem and not the OS or hd.