WIN XP PRO Uncommanded shutdown and power off problem.

[Gusto]

I have a homebuilt computer running WIN XP PRO on an AMD processor.
This computer has recently developed a problem that is exhibitied by
uncommanded operating system shutdowns followed by a power off. All
facets of the shuttdown appear to be normal and when the system is
restarted it appears to start normally with no error messages. There
also does not appear to be a time correlation and there is no apparent
initiation action.

I originally thought this was an overheating probem so I changed both
the power supply and the processor cooling fan and added a larger heat
sink on the processor. This has had no effect.

Any help would be appreciated.

 

[Nepatsfan]

Have you checked Event Viewer to see if there are any entries
related to these events?

There's always the possibility that you've got a virus. You might
want to take a look here:

http://www.microsoft.com/security/incident/blast.mspx

You also might want to run as many online virus scans as
possible:

http://windowsxp.mvps.org/scanners.htm

 

[Gusto]

No, have not checked the event viewer, how do I get to it?

But I have done the other things you recommended. We ran several
virus scanners with no results, also went to the website you
recommended and downloaded the malware remover and ran that with
nothing found.

Thanks for the input.

 

[Nepatsfan]

For Event Viewer go to Start -> Run.
Type eventvwr.msc in the Open box and click OK.
Look for any entries that may coincide with these shutdowns.
Note: in order to see any entries in the Security section, you
have to turn on auditing of Account logon events. Here's how:
Go to Start -> Run.
Type gpedit.msc in the Open box and click OK.
Navigate to:
Local Computer Policy \ Computer Configuration \ Windows Settings
\ Security Settings \ Local Policy \ Audit Policy
Double click Account logon events and check success and failure.

Here's a Microsoft article that you may find helpful:

http://support.microsoft.com/kb/320299

Here are a couple of ideas that I'd call long shots at best:

Do you have a UPS backup battery attached to your PC? It's
possible that a power sag is triggering the shutdown function of
the UPS. If it's not setup to warn you then it would look like a
normal shutdown.

Take a look at Control Panel -> Power Options.
On the Advanced page change the setting under "When I press the
power button on my computer" from Shutdown to "Ask me what to
do". There's an outside possibility that the button on the front
of your case may be defective.

Are there any programs installed on your machine that have a
system protection feature? Any that monitor for problems? I know
you've addressed the heating and power areas but there could be
other issues.

I'll post back if I think of anything else that might be useful.

Nepatsfan