computer keeps restarting?.

Hi!. Im having trouble with my computer, It keeps on restarting,It isnt hot, I have done a defrag,virus checks,spyware check,system restore, I have even turned off the auto restart and it still does it. Any help will be greatly appriciated, Im not that good on the with computers and could really do with the help. Thanks heaps in advance.

Is this a new problem? Did it work OK previously?

What are you doing when it restarts? Is it after a certain amount of time?

What makes you certain that heat is not the issue? Are you monitoring your CPU and GPU temperatures as it restarts?

Any errors in the Event Viewer? If you are not familiar with the Event Viewer check out the Sticky post at the top of the forum: BSOD Diagnostics

Hi, thanks for your reply.
It has been doing it for a few weeks now.
I can be doing anything on the computer when it restarts and it can be random times.
It cant be hot if it does it first thing in the morning can it?. I start it up for the first time then it restarts about 3 or 4 times before i can get into it and then it does it randomly all day. How do i monitor the temp?
I have checked in the event veiwer thing and it had a few red crosses, one is WinDefend and cdrom. Does this make sense?.
I willgo check out the BSOD Diagnostics post.
Im trying to do this as fast as possible before it restarts agin, it has done it 5 times since i posted this first post.
Thanks again

A CPU can overheat in a few seconds.

Details on the errors would help us help.

This is described in the BSOD post.

Is the computer old? What is the make and model?

Have you ever opened it up and cleaned it?

A failing PSU (Power Supply Unit) could also cause such behavior.

Actually the computer is old, Ive had it for over 2 yrs and i think it was about 5 years old when i got it and i have never opened it up to clean it, I didnt think you could. Yesterday i got behind it and found a heap of dust on the vents which i cleaned. How do i take it apart to clean the inside?.
I will go back to my event veiwer and try find out more details on the errors.
thanks for your quick responses.

What is the make and model of the computer?

If you found that much dust outside that could be the issue inside.

Its a Intel Celeron Processor,957MHz,256MB. Windows XP Home SP2.
DO I just take the cover off and clean away the dust?
Thanks

I was wondering if it was a Dell "such and such" or an HP "such and such" or ... etc.

Their web site would probably have detailed instructions. But basically open the case and clean it out. Avoid touching any parts. Gently using canned air is the best procedure. Do not blast air just take your time and gently blow out the dust. Check to make sure all the fans are working before closing it up.

Also good to read this:

http://www.d-a-l.com/articles/library/72.html

Maybe its a Tang professional computer?

http://www.tang.com.au/tang.cfm