PC Powers up then shuts down

Hi all. I built my first system about a year ago (specs below, with one difference) and it ran just fine for almost exactly a year. I came back from a conference to the dreaded words from my wife: "I don't know what's wrong with your PC, one minute it was working fine and then it wouldn't start." She had just been checking e-mail on the web, shut the machine down, and then when she tried to restart it later it would power up for a few seconds then shut down abruptly.

I've seen this problem described several times on the web, but with no clear solution. Here's what I have done. My original PSU was a Seasonic 550 and I actually did a check before I went away using the ASUS monitoring software that came with the board and all the power values looked good, as did the temps (the rig has always run pretty cool). Still, I figured that it might be the PSU, and I replaced it since I was looking to upgrade some of the components in the future. So it now has the PC Power and Cooling Unit listed in the sig.

No go. Same symptoms: PC powers up, all fans spin, it seems as if the HD gives a brief chirp, and then everything shuts down.

Tried clearing the CMOS since that seems to have worked for some people. No dice.

Any other suggestions would be greatly appreciated.
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  1. Perhaps the CPU is turning off to avoid overheating.

    Just to clarify my post: Sometimes a CPU can detect that it does not have proper cooling due to a loose heat sink or other problem, and turn off because it thinks it has a cooling problem when it fact it isn't overheating.
  2. Thanks for the suggestion, ghmage, I'd wondered about that myself. However the CPU fan and heatsink is still seated as firmly as it ever was (I've checked it repeatedly). This is also a problem I would have expected to show up almost immediately after the build. When I installed the CPU, I cleaned off the thermal material that came with it and replaced it with arctic silver. Since then, it's been the coolest machine I've ever owned: case temperatures in the high 30s, and MB and CPU temperature never getting much above 40 even when under heavy gaming load.

    So if it is shutting down for that reason, wouldn't it mean something has failed somewhere? If so, what?
  3. Interrogate the wife.
  4. So, now that I've arranged for a holiday for the wife to sunny Gitmo, any other suggestions? I really just want to know what components I should start spending my hard-earned dolleros on first.
  5. I would start with completely taking the PC apart and re assembling it and then testing each part. Starting with RAM, PSU, Motherboard, HDD, CPU, etc in that order.
  6. Hoping someone here can help - I'm having the same problem as Taniwha.

    Computer was working fine, then started to crash regularly w/ BSOD memory dumps. Figured it was the RAM, so replaced that. Once I installed the new memory, the machine began the "power on for 3 seconds and power down" sequence - never proceeding to POST. The problem persisted even when I put the original RAM back in (i.e., returned to original configuration).

    After reading up on the issue, tried replacing the power supply. Just got that installed - no change, problem persists. Also tried resetting the motherboard CMOS, to no avail. CPU is well greased and heatsink is properly installed and clean of dust. Also relatively sure there's no shorting issue, as I can get the machine to stay powered on if I hold the reset switch 1/2 way down after hitting the power button. This doesn't help w/ diagnosis however, because the system simply hangs and gives no display.

    Relevant specs:
    Motherboard (same as Taniwha): Asus M2N-SLI Deluxe
    CPU: Athlon X2 4400+
    Power supply (brand new): Rosewill RP600V2-S-SL 600W
    RAM (brand new): 2x 1GB Corsair XMS2 TWIN2X2048-6400

    Is my motherboard fried?!? Please tell me there's something I'm missing!

  7. I had the same problem. pc would run for 3 seconds then shut off. I just fixed it and found out that the front panel of my case was holding down the power button. As soon as I took off the front panel it released the power button and now pc stays on. You might want to check out and see if your power button is faulty. Before I found this out I swapped PSU's, reseated and changed heat sink compound on the processor, cleaned the motherboard really good to make sure there were no shorts, reseated all connectors, all with no luck. All to find out it was my front power button.

    Not to say this will fix all but in my case this was a fix and I hope it helps someone out.
  8. I have had a similar problem. I brought some stuff off ebay incuding a new cpu, graphics card and second hand motherboard. In the listing the motherboard was described as 'untested'. In heinsight, perhaps this was a bit foolish. Anyway, put together my new system, and the same problem occured. I'm using the same case as before, and after rebuilding my old system it is completely back to normal. So, in my case, it wasn't the front panel. I guess what i'm trying to say is that your problem may simply just be a dead motherboard.
  9. Quote:
    Power supply (brand new): Rosewill RP600V2-S-SL 600W

    You replaced a cr@ppy PSU with another cr@ppy PSU? :pfff:
  10. so how to resolve this problem
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