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Computer will not POST. Need help narrowing down the possibilities

Last response: in Systems
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March 17, 2012 6:22:16 AM

I believe that in order to understand the situation I am in I should tell the full story.

About a week ago while playing a round of Battlefield 3 my computer just shut off and would not POST nor emit any system beeps even though the fans were running. These are the specs of the old computer:

Motherboard: MSI P55-GD65
CPU: Intel Core i5-750 2.6Ghz (not overclocked)
Video Card: Radeon HD 4870 (not overclocked)
RAM: 6Gb (3x2Gb)
Power Supply: OCZ ModXStream Pro 600W

Although my CPU temperatures were always high this was the first time it had ever shut down like that so I figured that I had simply fried the processor. I did some research looking for new parts and bought a new motherboard, CPU, video card, and RAM.

Motherboard: ASRock H61M/U3S3
CPU: Intel Core i3-2120 3.3Ghz (not overclocked)
Video Card: Radeon HD 6870 (not overclocked)
RAM: 8Gb (2x4Gb)

I put together the new parts in my old case as usual yet when I tried to boot up there was still no POST or system beeps. I reseated everything and made sure all the power supply connectors were connected to the motherboard but still nothing. I decided to try the breadboarding technique described on these forums with only the CPU and power supply connected but still nothing. Since the motherboard and CPU were brand new I figured the power supply was the problem. Sure enough when I took the power supply from my brother's computer (Antec EarthWatts EA650 650W) and attached it to the new stuff I got the long system beeps signifying the lack of RAM attached.

I figured I had the problem fixed so I attempted just adding one stick of RAM and it would not POST or emit any system beeps again. I tried the other new stick of RAM and even the three old ones but none of them changed anything. Frustrated, I grabbed the old motherboard and processor which I thought were fried, plugged in the new video card and both of the new RAM sticks, and the system booted up normally. So basically even though all of the the fans (CPU, power supply, case) are running I figured out my power supply was dying or dead. Is that common? I am planning on getting a new power supply soon to replace it. The more serious problem is what is up with my new motherboard and/or processor? Could it be that only the DIMM slots on my new motherboard are dead? Or is it the new processor that is DOA? Sorry if this is too long but I would really appreciate any help in how I could narrow down these possibilities.

TL:D R

  • Computer crashed while playing Battlefield 3. Would not POST or beep even though all fans running.
  • Bought new CPU, mobo, RAM, and GPU but new build did the same thing.
  • Determined one source of the problem to be a dead or dying power supply using breadboarding.
  • Replacing power supply proved successful because computer would detect missing RAM with long system beeps while breadboarding.
  • After inserting one stick of RAM the computer would stay silent again no beeps at all. Is it the motherboard or the processor? This thread here indicates the RAM is shorting out the PSU but the RAM worked with the same PSU on the old motherboard.

    Haha I feel terrible even the TLDR is long. Thanks again for any assistance you guys can provide.
  • More about : computer post narrowing possibilities

    a b ) Power supply
    March 17, 2012 7:06:00 AM

    PSU would have been my first guess when it went down like that and wouldn't come back. What's your brand/model/wattage?

    Did you try the old ram (or some other ram) in the new board? Rarely some motherboards and RAM just don't get along. Its also possible the board is bad. Or you damaged it with the bad PSU. If your breadboarding properly and nothing can short I would swap the CPUs as a final check then RMA the new board as defective.

    Edit: Before bothering swapping the CPUs reset the BIOS if you haven't and try the memory again
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    March 17, 2012 6:21:55 PM

    Thanks for your reply.

    I posted the information you're asking about in the original post but I understand I probably made it too long so I'll try to be more concise here. I would swap the CPUs but my old i5 750 is socket 1156 and this new motherboard is for my new processor i3 2120 which is socket 1155. I will try resetting the CMOS and see if that helps any.

  • I took the new motherboard out of the case and onto it's box with ONLY the power supply/new CPU/system speaker attached. Not even RAM. The system would not POST or beep at all.
  • I switched out the OCZ 600W power supply for the Antec 650W power supply from my brother's working computer and I got the long system beeps indicating the lack of RAM. At this point I thought the problem was only the PSU so i was rejoicing.
  • I put in one stick of my new RAM, a 4Gb stick, and the system again went back to not beeping or POSTing.
  • I tried the other stick of new RAM and nothing. I tried all three sticks of my old RAM and nothing either.
  • Next, I got my old motherboard (MSI P55-GD65) and old processor (i5 750) which I thought had fried and installed both sticks of my new RAM and my new video card (HD 6870). The system POSTed as normal.

    Because the new RAM and new video card POSTed normally on my old motherboard I am assuming they are fine and are not the problem. The OCZ 600W power supply is at least part of the problem because I couldn't even get any system beeps with it installed. I'm thinking of getting this Rosewill Green Series RG630-S12 630W to replace it. The worrisome thing for me is even with my brother's fully functional Antec 650W PSU the system would not beep or POST after I inserted ANY stick of RAM. When there is no RAM installed it gives the long beeps indicating that it does not detect RAM but as soon as I insert any of the five pieces of RAM I have it goes back to not beeping or POSTing. Strange indeed.
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    a b ) Power supply
    March 18, 2012 2:27:14 AM

    K. it was late here guess my brain forgot some stuff after I read it LOL sorry. Just to be sure you have tried all the memory slots one at a time? I have heard of BIOS updates fixing problems like this but they found a stick of ram that would work(tried your brothers?). Double check the CPU install/look for bent pins if you haven't but it sounds like you've been very thorough. I would probably RMA the board. CPUs very rarely have issues. Since they bin the chips to mark them they pretty much have to be tested and working when shipped

    As for the rosewill PSU they used to make some iffy one but have started making some very good ones too. Hardware secrets review looks pretty good so I wouldn't be worried about using it.
    http://www.hardwaresecrets.com/article/Rosewill-Green-S...
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    March 18, 2012 3:54:30 AM

    Quote:
    Just to be sure you have tried all the memory slots one at a time? I have heard of BIOS updates fixing problems like this but they found a stick of ram that would work(tried your brothers?)
    I did try each stick of RAM at least once. Some of them in each of the four slots on the motherboard.

    Quote:
    Double check the CPU install/look for bent pins if you haven't but it sounds like you've been very thorough. I would probably RMA the board. CPUs very rarely have issues. Since they bin the chips to mark them they pretty much have to be tested and working when shipped
    I have not checked for bent pins but I will do that later tonight. Shouldn't there be a beep code for a malfunctioning/not detected CPU too? If that results in nothing I guess I will just RMA the board and hope for the best.

    Quote:
    As for the rosewill PSU they used to make some iffy one but have started making some very good ones too. Hardware secrets review looks pretty good so I wouldn't be worried about using it.
    Think I'll just spend a little more and go with Antec NEO ECO 620C 620W. Thanks for the help.
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