This computer shuts down every so often. No apparent reason and sometimes needs rebooting, sometimes just restarts and gives no message about not being properly shutdown. I have disabled automatic restart, doesnt seem to make any difference. Have taken memory out and put back again, updated drivers etc. Usually happens during the first 5 mins of booting up. It doesnt show up in event log. Any ideas please?

One thought, it could be the power supply overheating. Check to see that the cooling fan is spinning.

Have checked that and its seems fine. Thanks anyway.

You will have to set up your computer to record what is happining when it crashes if it even can. help and support for setup and recovery, see also event viewer. You may need to also do some diag's with software.

On the surface it feels like a heat issue somewhere. I concur with others to setup some 3rd party monitoring software to log what's going on. It could be something as simple as a BIOS setting that once the heat gets to a certain level = shutdown. Many newer BIOS are preset that way to make sure components don't fry. I think the settings are a little low but it's better to be safe than sorry.

Hi there hope you understand it because my English writing is not so good -)) I had a friend who has got the same probleme you subscribe. I friend of mine chat alot's on msn after 3-4 minutes pc reboots of himself. I coundn't think what the problem could be. reinstalled Xp no difference,replaced hardrive no difference.Finally i found it. The memmory was broken. Put in new ram memmory problem solved. Try it !

I would also suspect the PSU on random re-boots, especially if nothing else has changed. The PSU supplied with many cases is usually just not up to the job and if it does go, especially if it's not a current protected type, it's liable to take other components with it. Check the label on your PSU - if it's an un-branded one, or if it is a low wattage one - less than 300w I'd consider replacing it anyway.