On Mon, 27 Sep 2010 15:39:18 -0700 (PDT), "
wrote:

I have a Dell optiplex 330 desktop PC which will boot alright, the
windows desktop with the (i'm using Win XP )icons will show but just
for about 40 seconds and it freeze for about 10 seconds and everything
will go off. just at about the time that it will go off the processor
fan will run at a very high speed. when it goes of like this, the
power light will change from green to amber and there will be some
weak cracking sound (presumably trying to give a beep) from the buzzer
on the mother board. At this stage powering it up again will not work
unless it is unplugged from the mains for about 20 minutes and it will
repeat the above problem.
I disconnected the hard drive just in case its a virus but the
same thing happened and even in setup mode.
please help

Is the air coming from the rear fan cold, warm, hot, or very hot?

Open the box and try to figure out what is getting hot? CPU, RAM,
plugin cards, power supply, etc.

Make sure the CPU is properly seated and that the heat sink is
properly attached to the CPU. You symptoms sound very much like an
overheated CPU.

Look at the electrolytic capacitors surrounding the CPU and see if any
of them look scorched, melted, leaking brown goo, or have the tops
bulging. If that's the case, see:
http://en.wikipedia.org/wiki/Capacitor_plague
http://www.badcaps.net

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