Will a weak PSU cause my PC to restart at random?

I'm having a bit of a problem with my PC and I'm not sure how to go about finding the cause of the problem so I can fix it. I'll start from the beginning.

My husband and I usually keep our PC on 24/7 because we've had problems in the past about it going to hibernation mode and not wanting to come back out. Well about a month ago everything was running fine (we even bought and nice new energy star LCD 21" screen), then as we we're watching TV we heard a loud "pop" noise come from out PC followed by a burning smell. We checked it and didn't see any problems and it continued to run fine and nothing caught fire. It still ran fine a few days later but then it started to reboot itself at random times. More annoying then anything and we still weren't seeing any problems whenever he ran a check on the system. We though it was caused by low ram and got a couple gig sticks which would have been more then enough for what we run. But the problem continued. He reinstalled some video drives and when that didn't help he reformed the HD. Still nothing. So he restored the whole system. It seems to work for a few hours and just when we thought we'd fixed it, it restarted again! I got to thinking that maybe it has something to do with the PSU, but I'm not sure what is causing it. Today as it restarted on me for about the ninth time, it turned the keyboard off on the restart. It did this twice (the keyboard is wired to the front usb) on the last two restarts.

Does anyone have any idea what might be happening? And what short of buying/building a new PC can I do that is cost effective?

I'm surprised I was able to finish typing this without it restarting once (going on almost 1 hour now).

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  1. Would you please list your system specs (ie. CPU, Motherboard, graphics card, RAM, PSU brand) before anyone recommends any solutions? But it does sound like it could be a PSU problem and replacing it with a reputable brand from Corsair, Antec, Seasonic, Pc or Power & Cooling etc would be a cost effective solution.
  2. Best answer
    Yes, a PSU could cause that. The PSU has a small circuit inside that monitors the voltage outputs. If one of the outputs drops out of tolerance, the PSU is supposed to automatically shut down. When it does, it removes a control signal called something like "PowerOK". When that happens, it forces an automatic hardware reset.

    If the PSU does not shut down, really bad things can happen such as exploding components or flames.

    And with the system specifications, we can offer recommendations about appropriate size. Include any prospective upgrade plans also.
  3. its probably the PSU,but there is also a chance an electrolytic capacitor on the motherboard made that sound.Your safe bet is to try another PSU,and if this doesnt work out RMA your motherboard
  4. +1 jsc

    I would guess that what you heard was a capacitor failing.
    Surprising is that your system is still running after the component failed.

    I recommend changing the PSU as soon as possible and not using the system until it has been replaced.
    When caps fail in low end PSUs (if your system is a prebuilt one it most defiantly is) the voltage output gets very unstable and will kill your system with prolonged use.

    If you would post the model of your computer we can direct you towards a quality replacement PSU and instruct you on the proper procedure for replacement.

    This is the link with my stock system specs. I upgraded the video card a while back to an nVidia GeForce 6200 A-LE. When this first happened I thought it could be the RAM going bad so I got some from a friend from a reliably working PC. I am unsure of the brand, but the RAM was more than doubled. 1.25gb currently.

    My husband also checked the mobo for any blown capacitors and did not find any, but I suppose that could still be the case.
  6. Bumping to see if I can get anymore more replies since I posted the specs.
  7. It seems that soemthing has blown in your PSU (as jsc said).

    Your best bet would to just buy a new PSU with your system a 350w psu could be fine. I wouldnt highly reccomend it but seeing as your computer is pretty much a very low end computer you could buy a very cheap $10 500w power supply, but that may cause a problem again. Youcould would to buy a descent 350w psu, if you do make sure that it has the right needs for your computer (most likely 20pin and 4 pin). If you want to take the best possible option, buy a quality 550w PSU so that down the road if you ever build your own computer then you could easily take it out and use it.

    If your motherboard is blown, then you will most definatley have to buy a new PC or build a new PC, because you will not find those parts, and even if you do it would not be worth using.
  8. Thanks for all the input, as much as I'd LOVE to buy/build a brand new PC it just isn't in the funds at the moment. I'll look into the PSUs available to me.
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