Hello good folks at Daniweb !!!!!!
I have a Dell Dimention 2350 , Windows XP Home edition, SP2.
The computer just shuts down at time without error messages. I can be on the net or running any program. Then it just restarts as if I I pushed the start button. A few times , when it restarted, it loaded me into the page that you get when you tap F8 at startup.
I think it's clean from viruses. I have run Spybot and SuperAnti Spyware and AVG.
It has ZoneAlarm for a firewall and runs AVG antivirus. When I opened the inside of the case, it was very clean. No dust on the "fins" or any dust buildup anywhere. I ran PCPitstop and it said 3 drivers were out of date and I believe that I have updated 2 out of 3 of them.
I installed Advanced WindowsCare V2 Personal to see if that would help, but it didn't.
I also installed SpeedFan 4.34, to see if I could get a reading on how hot the processor was but I couldn't get the program to show the temp. All it would show was the fan rpm.
I don't know what else to check or download. Any and ALL help is much appreciated !!!
I did download an updated driver for the graphics controller, just because PCPitStop said it needed it. Itwas an Intel(R) 82845G/GL/GE/PE/GV Graphics controller, and I got it from Dell downloads. After doing that PCPitStop still says that I need to update that driver, along with a mouse driver and an Intel(r) AC"97 Audio Controller.

Also go to control panel>system properties, click the advanced tab & go to Start up & Recovery settings & make sure the Automatically Restart checkbox under system failure is unchecked. That will usually let you see a blue screen upon system failure so you can get the error message. That may give you a clue as where to start.