Is there a logfile.........

In Vista that logs system problems, particularly unexpected computer shutdowns? If so how do I find it?

Control Panel > Administrative Tools > Event Viewer

Then look at your System and Application logs.

Thanks for that. Checked Application and System logs. All I can find in system log was a confirmation of an unexpected shutdown. There is a lot of stuff there I don't understand.

I would suggest going to control panel - system - advanced system settings - advanced - click settings next to startup and recovery (3rd button down), then untick automatically restart. This will mean instead of automatic reboots you will be presented with a BSOD. That BSOD may or may not give you useful info pointing to what the cause is.

on that same page also check write an event to the system log is ticked.

Edited by Chrysalis (Wed 26-Jan-11 13:13:59)

Thanks for that. When it happens it shuts down. There's no BSOD. It's not happened for a few days now so fingers crossed.

Overheating? My old lappy would suddenly die like that. A quick hoover of the fluff-choked vents cured it!

Concur with 'overheating' diagnostic. Another symptom is constant running of fan! I use a can of 'air' which you can get from most PC stores, camera shops or, at better price, plumbers merchants.

Another cause may be a PSU which was already close to its limit, but with the passage of time its efficiency has degraded and certain conditions (heat, demand) can tip it over. A recent upgrade without consideration for the PSU's capabilities would certainly be a good suspect.

I'd second PSU as a possible cause, even without any upgrades. The cheap ones are bad enough when new, but once the capacitors have had a few years to age....

Many thanks to all for your suggestions. It's not happened again since I posted, but I'll keep an eye on the overheating suggestion.