Constant rebooting

[Mich]

I have a Dell laptop with Vista Ultimate on it. I've had this machine for about a year now. Roughly a month ago the thing started rebooting out of nowhere. It has never rebooted while I'm working on it. When I set it aside I will hear the reboot music and sure enough it is rebooting.

There's no virus here. I've set Vista to NOT automatically reboot when there is a problem and to write to the event log when it does. The thing still reboots, but it is as if the system doesn't know it because nothing is written to the log.

I'm leaning heavily that there is something to do with the laptop's power settings/options, but have tried just about everything. Any ideas?

-If it ain't broke, break it and make it better.

 

[linney]

Do you have any Schedule Tasks or login scripts which might be invoking Shutdown.exe to run?

Is Windows Update downloading to and then rebooting the machine?

Checkout some of the ideas and suggestions in this XP thread for any possible clues.

PC restarts regularly for no apparent reason !!
thread779-1395467

Have a look at this thread and see if you can filter out User32 in the System Log and get some reason for shutdowns?

W2K3 "Reason for reboot"

http://www.tomshardware.com/forum/216258-46-w2k3-reason-reboot