Computer turns on for a split second then shuts off

What's happening is when I try to start the computer it turns on and shuts off immediately. Case fans, CPU fan, GCard fan, case LEDs and PSU fan all turn on for that half second. If I press the power button again, nothing happens.. The only way I can get it to attempt to startup again is if I turn the socket on the wall off and on again but it still does the same Thing.


I built this computer last Wednesday everything was working fine then yesterday the PC would not turn on, it did what I explained above. To fix it all i had to do was change the socket on the wall and it booted up fine. Today the same thing happened except the quick fix did not work.

I have tested the psu using the paper clip and it runs fine.I just cant figure out how yesterday i could play BF3 and today it wont't turn on.

Some other things that might be worth mentioning:
I installed an extra 2x4GB Ram yesterday
The motherboard power led acts weird e.g takes 30 sec for it to turn of after turn psu off at the back

Specs:
amd phenom ii x4 965 BE
Corsair GS600
Asus M5A78L-M/USB3 Motherboard
Komputerbay 4x4Gb 1333Mhz Ram
Sapphire HD 6870

Thanks,
Reply to NuClArPeNgUiN
24 answers Last reply
More about computer turns split shuts
  1. Definitely the RAM. Take out each stick, put one in, and do a boot-up test.
    Reply to obsama1
  2. Make sure that your CPU power header is plugged in, i made that mistake before :lol: might have fallen out?
    Reply to spat55
  3. NuClArPeNgUiN said:
    What's happening is when I try to start the computer it turns on and shuts off immediately. Case fans, CPU fan, GCard fan, case LEDs and PSU fan all turn on for that half second. If I press the power button again, nothing happens.. The only way I can get it to attempt to startup again is if I turn the socket on the wall off and on again but it still does the same Thing.


    I built this computer last Wednesday everything was working fine then yesterday the PC would not turn on, it did what I explained above. To fix it all i had to do was change the socket on the wall and it booted up fine. Today the same thing happened except the quick fix did not work.

    I have tested the psu using the paper clip and it runs fine.I just cant figure out how yesterday i could play BF3 and today it wont't turn on.

    Some other things that might be worth mentioning:
    I installed an extra 2x4GB Ram yesterday
    The motherboard power led acts weird e.g takes 30 sec for it to turn of after turn psu off at the back

    Specs:
    amd phenom ii x4 965 BE
    Corsair GS600
    Asus M5A78L-M/USB3 Motherboard
    Komputerbay 4x4Gb 1333Mhz Ram
    Sapphire HD 6870

    Thanks,


    I had a similar problem for a recent build for a friend. The problem turned out to be the standoff the case manufacturer told me to put in was shorting the mobo. As the case already had risers for the mobo. So I would check that first just to see.
    Reply to Anonymous
  4. Thanks for the reply's

    obsama1 I tried what you said i toke all the stick out then just put one in but still no luck even with no ram in the same thing happens

    yarmock Atm the Mobo is out of the case on a sheet of cardboard so that's not the problem

    Spat55 Yes the cpu power header is in, weirdly though if i plug it out and power up it stays on
    Reply to NuClArPeNgUiN
  5. NuClArPeNgUiN said:
    Thanks for the reply's

    obsama1 I tried what you said i toke all the stick out then just put one in but still no luck even with no ram in the same thing happens

    yarmock Atm the Mobo is out of the case on a sheet of cardboard so that's not the problem

    Spat55 Yes the cpu power header is in, weirdly though if i plug it out and power up it stays on


    That is odd, try googling it? Don't know what that means!
    Reply to spat55
  6. Either the mobo shorting thing or:

    The heatsink isn't seated correctly. Try reseating it or using a different one.
    Reply to Collywozzle
  7. Collywozzle said:
    Either the mobo shorting thing or:

    The heatsink isn't seated correctly. Try reseating it or using a different one.


    I don't see how this could be the problem as it was working fine for nearly a week?
    Reply to NuClArPeNgUiN
  8. Also I have noticed if i turn the psu off at the back and short the power switch it powers on for half a second
    Reply to NuClArPeNgUiN
  9. NuClArPeNgUiN said:
    I don't see how this could be the problem as it was working fine for nearly a week?


    Reason here is that even if it may run fine, the seating can actually cause issues for booting. You may boot up and it work alright, but if it either trips the failsafes or shorts a connection on the board (less likely these days) it will prevent the boot. Note that if you try to boot without a heatsink it probably wont work and may beep or something (depending on mobo). However from my experience an incorrectly seated one can prevent boot but not show the usual signs.

    This was more of an issue 10 years ago - things have advanced somewhat since - but imo, is worth checking. reseating stuff like that is an easy check.
    Reply to Collywozzle
  10. Collywozzle said:
    Reason here is that even if it may run fine, the seating can actually cause issues for booting. You may boot up and it work alright, but if it either trips the failsafes or shorts a connection on the board (less likely these days) it will prevent the boot. Note that if you try to boot without a heatsink it probably wont work and may beep or something (depending on mobo). However from my experience an incorrectly seated one can prevent boot but not show the usual signs.

    This was more of an issue 10 years ago - things have advanced somewhat since - but imo, is worth checking. reseating stuff like that is an easy check.


    Should I take out the cpu aswell?
    Reply to NuClArPeNgUiN
  11. Ok i reseated the heatsink but still no luck D: any chance the Motherboard is dead?
    Reply to NuClArPeNgUiN
  12. A similar thing happened to me, then I discovered I accidentally plugged the CPU power into the 8 pin PCIe power connector on my modular PSU. Switching the connection to the right place fixed everything. Is it possible that this happened to you?
    Reply to moornix
  13. moornix said:
    A similar thing happened to me, then I discovered I accidentally plugged the CPU power into the 8 pin PCIe power connector on my modular PSU. Switching the connection to the right place fixed everything. Is it possible that this happened to you?


    sadly no both are labeled pci-e and cpu so frustrating :fou:
    Reply to NuClArPeNgUiN
  14. Is it possible the motherboard is dead?
    Reply to NuClArPeNgUiN
  15. On the power supply plug I have a 2 pin to 3 pin to fit the socket on my wall could that be the issue?? Because i can recall that there was a surge warning that came up a few days prier to this before the boot screen.
    Reply to NuClArPeNgUiN
  16. NuClArPeNgUiN said:
    Thanks for the reply's

    obsama1 I tried what you said i toke all the stick out then just put one in but still no luck even with no ram in the same thing happens

    yarmock Atm the Mobo is out of the case on a sheet of cardboard so that's not the problem

    Spat55 Yes the cpu power header is in, weirdly though if i plug it out and power up it stays on



    I had that same exact problem. Its a dead motherboard. I RMA'ed mine to MSI and got a new one. But be forewarned, when mine died, it also took the CPU with it, so consider the possibility that it fried the CPU as well..
    Reply to velosteraptor
  17. velosteraptor said:
    I had that same exact problem. Its a dead motherboard. I RMA'ed mine to MSI and got a new one. But be forewarned, when mine died, it also took the CPU with it, so consider the possibility that it fried the CPU as well..


    Hopefully that is not the case with me :S I did the paperclip test on my PSU it passed with 1 fan attached but failed with 2 so I'm returning it. I'm praying that it didn't take anything else with it xD :L
    Reply to NuClArPeNgUiN
  18. NuClArPeNgUiN said:
    Hopefully that is not the case with me :S I did the paperclip test on my PSU it passed with 1 fan attached but failed with 2 so I'm returning it. I'm praying that it didn't take anything else with it xD :L



    Good Luck haha. Hope it didnt fry anything else
    Reply to velosteraptor
  19. Hello to everyone browsing this thread. I thought I would come back and explain how I fixed the issue.

    If you are positive everything is hooked up and installed correctly, the problem is more than likely your power supply.

    The power supply may have the necessary wattage for powering your device, but could lack in other areas such as amps (which many product pages don't have info for). If you decided to buy a relatively cheap power supply, this is more than likely your issue.

    I built a PC with a GTX 970 and AMD FX 8 core CPU. The PSU was 650w, which was more than enough in terms of wattage, but I ran into the same issue because I decided to use a $50 PSU.
    Reply to zharvey
  20. Try to reseat the hard drive and the cables that is connected to your hard drive and psu
    Reply to PATRICKCTHN
  21. To anyone who came here as the result of a Google search (like I did), my problem was that one of the the RAM sticks wasn't properly inserted.
    I don't know how it happened because I clearly heard the "click" it normally does when the stick is fully inserted and locked in place. Anyway, I removed one stick and my computer booted fine. Then I reinserted the stick I had removed and made sure it was properly inserted, and again the computer booted normally.

    Hope it helps anyone else who came here desperate like I was :)
    Reply to rafaelgduarte
  22. My new computer worked fine until I started tidying up the cables, and I moved the CPU power cable to another spot on my modular PSU thinking it was exactly the same. After reading this thread, I moved it back where it was before and it's working again. Thanks Moornix and Spat55 for their responses as this helped me to solve my problem.
    Reply to Ryan_194
  23. spat55 said:
    Make sure that your CPU power header is plugged in, i made that mistake before :lol: might have fallen out?


    This post/reply maybe 4 years old but my derp self did exactly this. Thank you. lol

    Mine didn't fall out I actually had to remove it to replace the current GPU power with a newer cable for a newer GPU. I blame excitement on my mistake. xD
    Reply to Duff72
  24. zharvey said:
    Hello to everyone browsing this thread. I thought I would come back and explain how I fixed the issue.

    If you are positive everything is hooked up and installed correctly, the problem is more than likely your power supply.

    The power supply may have the necessary wattage for powering your device, but could lack in other areas such as amps (which many product pages don't have info for). If you decided to buy a relatively cheap power supply, this is more than likely your issue.

    I built a PC with a GTX 970 and AMD FX 8 core CPU. The PSU was 650w, which was more than enough in terms of wattage, but I ran into the same issue because I decided to use a $50 PSU.


    I appreciate that you took your time to post this conclusion. I had the same issue. Everything plugged well but the pc won't boot when an extra fan was added. The PSU is in deed a cheap one, and this might be the problem. I'll just not plug the other fan.
    Reply to VonHamersmark
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