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PC dying? Runs 2-3 sec., stops. Sharp impact, runs.

  1. Apr 9, 2015 #1
    I have an old Windows Vista PC that has started acting up. Normally it is in the sleep mode. Lately when I push the start button the fans start running for 2-3 seconds and then it shuts down. This can happen many times in a row but if I lift one side of the computer case a bit (which lies flat on my table) and let it drop back to the table the impact gets the computer working.

    All the fans appear to work, the pc battery reads 3.19 volts, the memory was removed and reinstalled.

    Any suggestions what might be causing the trouble that a violent physical impact temporarily fixes?

    Thanks for any help!
  2. jcsd
  3. Apr 9, 2015 #2


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    I'd take it apart and clean it. It may have cobwebs and other junk sucked inside.

    Next I'd reseat the cards.

    Is there any beep codes? They will indicate the problem too.

    After that, you probably need to bring to a PC repair center.
  4. Apr 10, 2015 #3

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    Also, turn it on with the case open. Are all the fans spinning? Some of them are not easy to see when the case is closed.
  5. Apr 10, 2015 #4
    Running with case open so all three fans visible.
  6. Apr 10, 2015 #5
    I don't think this pc has any cards just memory. I don't think there are any beeps but will take more care next start up.

    This was a cheap pc from Costco that has lasted for more years then I can remember, at this point just curious what can be fixed by a sudden shock.

    Would a failing hard drive cause a pc to shut down after only a few seconds into the startup process?
  7. Apr 10, 2015 #6

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    Which three are they? Specifically, is there a power supply fan? Two? Can you see it/them?

    If you take out the cards and drives, does it start?
  8. Apr 10, 2015 #7
    With the case cover off you can see the case fan, cpu fan, and the power supply fan, they all run. There are no cards but will remove the drive tonight.

  9. Apr 10, 2015 #8
    Sounds like somewhere there is an imperfect connection, but a physical jolt is sufficient to make the connection firm, at least temporarily.
    The poor connection could be just an internal cable somewhere, so it's probably worth trying unplugging all cables then plugging them back.
    Could be it's part of the internals of something though, such as the hard drive,which means there's not a lot you can do about it.
  10. Apr 10, 2015 #9
    Having time to play with the pc tonight I started it up and now, of course, it works! But that turned out to be good, it works and I can now experiment.

    I disconnected the two plugs to the hard drive and started it up. The computer starts and tells me there is no hard drive or something to that effect. Reconnect hard drive.

    Disconnect memory and start computer, now fans run and blank screen. Reinstall memory.

    Disconnect cpu fan plug and bingo, when I start the computer it runs for two seconds and shuts down. So either the connection is bad or the fan is on its way out.

    Thanks for all the input!
  11. Apr 21, 2015 #10
    One of the problems may just be the fact you are running Windows Vista. Try upgrading to 7; you'd be amazed at the performance difference it makes :)
  12. Apr 21, 2015 #11


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    The newer Pentium processors run so hot, the fan must be working at high efficiency at all times to prevent the CPU from overheating. When the CPU circuitry senses that it might overheat, it will immediately shut down.

    There is a thin layer of thermal grease/paste which is applied to the mating surface of the CPU with the fan/heat sink. The thermal paste/grease ages over time and loses its effectiveness in allowing the transfer of heat from the CPU to the heat sink, which results in higher operating temperatures for the CPU.

    If your fan is clean and there is no dust or any other obstruction blocking air flow, you may have to take the fan/heat sink assembly off the CPU, clean both the CPU and the heat sink mating surface, re-apply the thermal paste between the two, and re-assemble the CPU and heat sink. If you think the fan is dodgy due to age, it might be worthwhile to replace it and the heat sink, especially if you plan on keeping this computer running.

    In any event, it's a good idea to keep a tube of cleaner and a tube of thermal grease handy in your tool kit to deal with these kinds of emergencies.

    It's also a good idea to install a CPU monitor utility on your system which shows the core operating temperature.
  13. Apr 21, 2015 #12
    Last edited: Apr 21, 2015
  14. Apr 21, 2015 #13
    Taking SteamKings advice I popped off the CPU heatsink and the thermal grease did look a little dead, new grease (High Performance Thermal Compound). The computer had been working ok for a about a week but shutdown on startup tonight. Popped of the CPU fan and got the model number, Googled it, ordered it, $20 with shipping, hope that was the problem.

    I have a air compressor and from time to time blow out the PC's in the house.

    Thanks for all the input!
  15. Apr 23, 2015 #14


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    The first thing you do when your computer seems to quit working and there is nothing obvious (and some other times as well) is to remove and reseat all the connectors. That means peripheral cards, memories, disk drives, power, everything, and if all that doesn't fix it, the CPU itself (I save the CPU for last, and it needs new grease). Also, any thing that is socketed.

    Of course, boot progress indicators, beeps, etc, for the model you have, should be investigated first.

    Then I start thumping things. Sometimes there is a bad solder joint.

    I would expect reseating all connectors will/did fix yours. A shock like you described probably temporarily fixed a bad connection.
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