Unexpected Reboot

I too am having problems with unexpected reboots but they happen regardless
of whether I am using the computer or not (as a matter of fact, it happened
while I was writing this!). I already have the setting to not reboot but it
reboots anyway. I don't play games and I have antivirus, antispyware, and
firewall software installed. I first suspected a hardware problem but all
diagnostics show no problems and despite that Dell replaced the power supply,
cooling fan, etc. The system is WinXP SP3 on a new Core 2 Dell Inspiron 530
with 3 GB RAM. I have tried reinstalling Windows and shutting down each piece
of software that I use. I have a brand new APC UPS. Nothing seems to make any
difference. Help!

"Unknown" wrote:

You should go to control panel --system--advanced --and change the setting for
when an error occurs to NOT reboot. Do this so that if the error occurs you
can investigate its cause. Do forget to look in the event viewer.