Computer powers on, then off again immediately

Hi guys,

My homebuild from a while back has cacked out and I'm trying to run down the issue. Specs as follows:

Mobo: Asus M2N-SLI Deluxe
CPU: AMD Athlon X2 BE-2300
RAM: 4 x 1 GB Corsair TWIN2X2048-6400C4
Video: 2 x NVIDIA GeForce 8600 GT OC 256MB

Ran for years without much in the way of issues. At first it was powering up and then dying as soon as the DVD drive power up noise came on. I would not get any beeps.

Soon after that, the power on button just wouldn't do anything. I could get it to try to boot by toggling the power switch on the PSU, but it would do the same thing.

I have tested the power button, and that is not the issue. I have also tried a known good PSU, and the results were the same. I have tried it without RAM in there, and I get one long beep and then it powers down again. Popped the RAM back in and was back to the original problem.

I recognize that it's more or less an ancient system at this stage, but I'm really trying to hang on for another year or so so I can save up the coin for a better rig.

Thanks for your help.
17 answers Last reply
More about computer powers immediately
  1. Have you tried to boot with just one RAM? Alos you can toggle them in different Slots, one at a time.
  2. How well is your CPU cooler seated? I'd take it off, clean everything thoroughly, and reseat the cooler with new thermal paste. This sounds similar to an issue I was having that turned out to be the CPU overheating very quickly.
  3. Yes, I have tried putting the RAM in several different ways but no luck.

    I was under the impression that the RAM wouldn't be at the root here since I would at least expect it to POST. I did have a RAM issue on this one a while back but it was only when it tried to load the OS that I would get the BSOD. Is this not the case?

    As far as I can tell the CPU cooler is still seated. I'll have to grab some thermal paste and try. It wouldn't have taken any big impacts lately since it's just sitting by my desk...
  4. Did you say years? A motherboard can be damaged by dust and such if its homebuilt.
  5. I also thought it was the PSU, but I took a multimeter to it and it checked out. I also bought a new PSU this morning and tried it with that, but it acts the same.

    My current thinking is the motherboard kicked the can, but I'm hoping someone has another idea since if the motherboard is gone, the whole rig is effectively kaput.
  6. cpu or mobo. but since you have multiple problems, dvd, etc. I think the mobo is shot. you said you eliminated the ps.
  7. And yes years...this is a late-2007 era box.
  8. I dunno, don't give up on the MOBO yet. I think if you've had the thing since 2007 and haven't cleaned out the CPU heatsink or anything it could be a heating problem. Have you tried running Core Temp or some other monitor while it's running to see your temps? Have you noticed that the PC is unusually loud before it shuts off?

    Could be totally wrong of course, just that this sounds a lot like what happened to me.
  9. Remove all unnecessary devices. Just boot with one graphics card, Mainboard, CPU, PSU, one RAM.
    Disconnect HDD, DVD and USB devices (mouse, keyboard)

    If that doesn´t work, replace the CMOS battery of the mainboard with a new one and try again.
  10. No, Just MOBO, CPU, and RAM. The graphics card is power intensive, unless the graphics are built in. Check if it posts.
  11. Okay, I removed both video cards, the HDD, and the DVD drive. The only thing left is the MOBO, CPU, and RAM. No change.

    I popped out the CMOS battery and metered that, and it still shows 3.1 V so I would think that it too is fine.

    The CPU heat sink certainly has some dust in it that could stand to be cleaned out, but nothing too too excessive.

    Photo, if at all helpful:

  12. Oh and on the temperature question, I hadn't noticed any excessive fan use before. It does have some temperature monitoring, but since it doesn't POST I can't get to it.

    Would it really overheat within a couple seconds if the thermal paste was cracked?
  13. old thermal paste should be replaced. yes, it can get too hot in a second and shut down. and if the heat up got too bad it can kill the processor. hear any clicking in the processor area?
  14. No clicking. The only change has been that once I took out the video cards, the fan doesn't start up at quite as high of a speed.

    What should I be using to remove the old thermal paste?
  15. rubbing alcohol and a cotton rag.
  16. iknowhowtofixit said:
    All this work for a tired, old, and dead mobo...

    that was my first assumption ( see above )........... but...........
  17. Yeah, I have the same reaction I had just wanted to try to save a bit more for a new one but I think I'm going to bite the bullet and just replace it. Thanks for your help all the same everyone.
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