Hi there, My son's computer recently started having this problem in which, after 5 minutes of the computer running, and running fine at that, it suddenly closes down immediately, but yet, is not switched off: the power button which usually is a constant green starts to slowly flash yellow and the only way to stop this is to switch the computer off. Whenever he switches it back on it does the same thing, works fine for 5 minutes and then switches to nothing but the flashing yellow light, we have even tried it in safe mode and the same thing happens. Just to give some info which might help you, the computer is a Dell Dimension 5000 running windows xp home edition. The last time before the problem started, the computer had been left on for around 20 hours, and this has been happening for around 12 hours now. He did replace his graphics card recently, but that was 3 months ago and he hasn't noticed anything wrong with it in that time Is this easily fixable or will a professional have to be brought in, and if so would it just be worth backing up the necessary dataand buying a laptop to replace it, as he is off to university in a couple of years so will need a new computer soon anyway. Well thank you in advance, just ask if you need anymore information about the computer, i'll do my best. Thanks!
Could possibly be a psu failure, enough power to the mobo but not enough for the hdd. Does the pc re-boot as soon as this happens or does he have to wait a wee while? Other possibility is the CPU fan cogged and not cooling the cpu properly. Chech Woodchips' advice too as that is a distinct possibility.