Sudden laptop shutdown
I've got a Philips x67 laptop with windows vista o/s and whilst it seems to work ok most of the time it occasionally switches itself off for no apparent reason. It shuts down as if you have held down the power switch to force a shut down. When I restart the computer it seems normal but does say that windows closed down with error but doesn't give me the opportunity to repair. The shutdowns occur sometimes as vista starts sometimes it can run for hours and not shut down.
I've loaded all the upgrades to windows. The laptop also doesn't do this when running on the battery it's only when connected to the mains.
Any suggestions anyone?