On thurs and fri I had a problem where I got a blue screen with a window xp error message on and my comp shut down. It would not then restart it was completely dead, the only things which worked when I pressed the button was the fans, there was no bios beeps or anything. If I left it off for say 30 mins it would then start up fine. My local comp shop said it could be a virus so yesterday formatted everything and did a full reinstall of everything and virus scan which showed nothing and the comp would start and reboot fine.
Then today I started it and went on the net for a bit and tried to do a restart and the thing shut down and went dead on me again. I think its some sort of intermitant hardware failure and was wondering if it could possibly be the processor overheating or something as if it is dead if I leave it for say 30mins it will then boot ok.
The problem only seems to occur if I try and reboot the machine if I keep it running it seems ok.
Anyone got any ideas?
TIA

Well, something really seems to be overheating here.. check the CPU fan, but also keep an eye on the video card - some of them can run quite hot.

Its driving me nuts cause it seems to be an intermittant problem. I've had the comp running for an hour or so now and seems fine. I restarted it and it did OK.
Now next time I try to restart it might go dead on me.
Is there a way of finding out what the temps are inside the casing [using windows and not the home thermometer] and what should they be?.

This is most likely an intermittent hardware failure. It could be any component of your PC that is malfunctioning.

Try a bare bones boot to narrow the search for the malfunctioning hardware device:

This test takes only a few minutes. It sounds difficult, but in practice is quite easy. Take notes if necessary on the devices you disconnect so that you will have no difficulty putting everything back together:

1) When you open the case, make sure that all fans are working, that the heatsinks are not clogged with dust, and that the motherboard appears to be normal – no bulging, leaking or exploded capacitors.

2) Disconnect power and data connectors from all drives (CD, DVD, HD, floppy) leaving only your boot hard drive. Remove any cards from the expansion slots except your video card. Disconnect any devices attached to serial, parallel, firewire or USB ports

2) Try to boot. If the problem has gone away, add devices back one at a time until you discover the defective component.

3) If the problem still exists, you have narrowed your search to motherboard, memory, CPU, hard drive, video card and power supply.

Further Testing:

1) See if machine will boot or whether it still crashes in Safe Mode.
2) Try a different video card if possible.
3) Test memory if possible with DocMem or other software memory tester. If machine won’t boot, remove one memory stick then the other if you have two, or try another compatible memory stick.
4) If machine will boot but crashes randomly, the CPU is probably okay, otherwise try a different CPU.
5) Look at PSU voltages with voltmeter – (red is 5 volts, yellow is twelve volts, black is ground). Or enter bios setup and read the voltages. If machine won’t boot try different PSU.
6) If all other components test okay, motherboard may be the problem.

That Xp shut down message sounds like something called the saesser worm (don't quote spelling), that was created by some german guy and it only effects Xp and 2000. Ok enough blabbing, your computer working then not sounds to me like Cpu overheat. Is your computer D.I.Y built. Some motherboards have a Cpu overheat function, that shuts the computer down if it detects the Cpu overheating. The reason I ask if its D.I.Y built, is because you should when installing the Cpu and heatsink, spray some thermal grease between these two components to improve heat disapation. The heatsink should have a pad on the bottom of it that improves heat disapation but it is dibaitable weither you also need thermal spray as well. If its not, I don't really know, theres one thing I've heard about, if your extractor fan, the 1 at the back, is setup to run faster than the others you can draw in dust clogging up fans, and likewise if you don't have enough or right fans the computer can overheat. Oh well, i'm kind of blabing now. Hope I could be of some sort of help. Best of luck

Also check the Powersupply Fan... Mine died recently causing a heatup in the entire system until it halted my system.

General - check Fans and Power - dust (makes things hotter or work harder)

Power surges can cause stuff to start failing intermittently too...

I think gwallen4 is offering good advice. I am sure his logical procedure will identify the culprit for you.

However, since there has been a mention of the Sasser worm, and the symtoms for the worm are computer shutdowns, I have posted the following link - checking this out will give you peace of mind.

Always use a Firewall as well as an Anti Virus program!!


http://www.microsoft.com/security/incident/sasser.mspx

Good luck;)