We have a PC with Windows XP that is frozen up.  The monitor screen is
black, with nothing coming from the PC. The light on the tower is on,
so it looks like it has power. I have tried holding in the power
button to try and power down and back up, but it never shuts off no
matter how long you hold the button.  I have tried disconnecting the
power cord, which does cut the power.  However, when you plug it back
in, it still does not reboot.  Is there usually another reset button
somewhere? What else can I try to get it to boot back up?

---

Request for Question Clarification by sublime1-ga on 26 Oct 2006 21:53 PDT

vikefan37...

I would suspect your power supply. It might still be providing
power to the CPU and/or case fans and lights, but still be 
failing to provide a proper or stable voltage to the video
card by way of the motherboard. I've seen it before...in 
fact, recently.

One bad design flaw in most power supplies is that they have
at least one fan which sucks air out of the power supply 
through the back of the computer. Some even have an additional
fan blowing air into the PS from inside the computer. Either
way, all the dust (some of which tends to collect on the inside
of your computer) gets blown from the inside of your computer
and through the power supply. And, of course, the power supply
warranty will be voided if you open it up to clean it out.

Without being cleaned, power supplies collect an astonishing
amount of dust, which can eventually cause significant problems.

One symptom which will tell you for certain that it's the
power supply is, after disconnecting the main cable from
the motherboard, and all peripheral cables from the hard
drives, CD & DVD ROMS, floppy drive and fans (with the 
main power cord removed from the power supply), plug the
main power cord back into the power supply and switch it
on. If you can hear a very high-pitched whine by placing
your ear close to the power supply, it's a sign of a
'leaky' capacitor, and a bad power supply.

Whoever sold you the computer may have the capacity to 
test the power supply, but it wouldn't necessarily be
a conclusive test. I had one with a whining, leaky
capacitor that tested okay, according to the test staff,
but replacing it brought my monitor, and the rest of the
computer, to life.

Let me know if this helps...

sublime1-ga

A similar problem happened with my PC couple of days ago.  I unplugged
it for about an hour before reconnecting and it booted back up.  Don't
know if same process would work for you.

Is this a lap top or a desktop?

It is is a lap top, unplug it and pull out the battery.  While
unplugged and without the battery in, hold down the power button for
20 second to discharge any residual charge.  Then put it all back
together and plug it in and see what happen.

If it is a desktop, you unplug it and the light on the tower goes off,
you plug it back it, do you hear anything, or see the harddrive light
flashing at all?  (Is the computer doing anything)

had similar problems supporting dell pcs. not sure if you're using a
dell or not.  fixing it involved removing the power, removing the ram
and in some cases the cpu for a few minutes and the putting everything
back in and powering up.  this was the recommendation from dell
support and it worked every time.