I have a C610 running XP Professional that shuts down intermittently...no apparent regularity to the time. Happens both when on battery and docking station. Control Panel power management settings are correct (Never-when on AC power, etc.). It's not a normal Windows shut-down; the unit just turns off. It will also refuse to start up, lights flash, then it turns off, prior to any apparent boot action. (Have noticed this happens shortly following a shutdown, but haven't confirmed it happens after the unit has been off.) Plenty of space open on the hard drive (8GB).