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I have an XP machine. When you push the power button, it beeps, seems to boot up for anywhere from 1-5 seconds, then shuts off. Here's the curve ball: It randomly starts up correctly! Whenever I come and try to reproduce the error it works fine. Anyone have a clue as to what's going on?

It's a desktop machine, not a laptop. Which means it's plugged into the wall and I'm fairly sure It's getting a steady supply of power.

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It's really very simple... your computer likes to make mischief! –  Aeo Dec 9 '10 at 18:39
    
Does it happen while plugged in or running from battery...or both? –  CaseyIT Dec 9 '10 at 18:41
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@Aeo: The whole network does.... –  John Dec 9 '10 at 18:50
    
@CaseyIT: Plugged in. It's a desktop so it's never running from battery. –  John Dec 9 '10 at 18:50

4 Answers 4

up vote 3 down vote accepted

It could be, in order of suspicion:

  • Bad power supply.
  • Bad incoming power to the power supply.
  • Possibly you have too many devices drawing power inside your machine.
  • Bad RAM.
  • CPU is overheating and automatically shutting down. Clean heatsink, or remove CPU, reapply thermal paste, and reinstall.
  • Expansion card, such as graphics card or other PCI/PCI-E device defective.
  • Bad hard drive.
  • Anything else attachable to the system might be causing something wonky, such as a keyboard or USB device.
  • Defective motherboard.
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Wow. Rats! I was hoping to not get "it could be anything" answers. I guess that means I have to take it apart and inspect it anyway... –  John Dec 9 '10 at 18:53
    
The infamous "Search and replace" has revealed it to have been the power supply. –  John Feb 9 '11 at 18:15

It would have nothing to do with your software. This happens straight away when you power it up, so something hardware related is causing the problem. You may want to look up your motherboard and find the manual for it, chances are they have an index describing what each beep code means. My bet is a loose connection or power supply issue. Is the machine connected directly to the wall and getting sufficient power?

Since it works 'sometimes' I am going to rule out bad ram or heat issues. I highly doubt it's your hard drive or video card. Whatever the fault is, it's soon going to die completely unless it is just a loose connection.

When it works 'sometimes', are there fewer devices drawing power from the same source as the machine?

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Good point that it could be other things attached to the same wall socket or power source as the computer. –  ultrasawblade Dec 9 '10 at 19:12
    
Yeah either that or the capacitors inside of the power supply/motherboard need to drain their charge before it works again. Could be temperature related too, but I kind of doubt that. –  qroberts Dec 9 '10 at 19:13
    
"from the same source" Same wall outlet? A phone, the monitor, and a network switch. The phone and network switch stay on. It has powered up with the monitor on and off. –  John Dec 9 '10 at 19:38
    
Okay I doubt it is an issue with getting enough power. Since it beeps once, I am sure it has something to do with the power supply (PSU) itself or a motherboard fault. If you have a spare PSU laying around you should try seeing if it works with that. –  qroberts Dec 9 '10 at 19:40

A good cleaning won't hurt. You'd be surprised how much dirt and crud can collect inside of systems. While you are cleaning, also take a look at all of the cards and cables to make sure they are seated correctly. Look for any signs of damage such as failed capacitors (they often have puffed or leaky appearance).

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Check the power button also. If it is spring loaded, it can sometimes get stuck in. Many computer will turn themselves off if the power button is held for 4 or 5 seconds.

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