New computer build won’t POST


I'm in the process of building my first PC and I've run into a situation where the computer won't post. I've spent about a week trying to diagnose the failing hardware component and I'm about to throw in the towel. I found many resources online in which others have ran into the same problem, however I still have not found a solution to "my" issue.

Problem: New build computer doesn't post. It begins to boot up, but powers off after 5 sec. It then repeats this cycle of booting and powering off indefinitely.

Attempts to Solve

  1. Reviewed many online forums as well as troubleshooting documentation ( This helped me verify that all connections are correct.

  2. Assembled motherboard outside of case (on motherboard box, not on anti static bag). Installed CPU, fan, and also the fan in. Tried to boot, received 3 beeps as expected (b/c of no memory). Added 1 stick of RAM (also tried 2 in dual channel mode, as well as all 4), tried to boot and received no beeps. The computer began to power on, but turned off after 5 sec. I then added my GPU and plugged power into it. Again, received no beeps and power turned on for 5 sec before turning off.

  3. Suspected PSU to be failing. Bought Corsair – Gaming Series 700-Watt ATX CPU Power Supply, received same exact results.

  4. Suspected either motherboard or CPU to be DOA, so I replaced them. Same results.

  5. Tried all 4 sticks of RAM in various combinations to determine if RAM is failing. Will not boot in any configuration.


  1. Could my GPU be DOA? I tried booting the computer without the GPU (same results), but my motherboard does not have an integrated VGA. I still expected to hear a post beep, even if I have no visual. Is this true, or do I NEED my GPU plugged in since I don't have an integrated VGA?

  2. Could all 4 sticks of my RAM be DOA? This seems highly unlikely, but I have heard mixed reviews about the quality of PNY XLR8 DDR3.

  3. Could it still be the PSU? I've checked the both PSU's by doing the paper clip test. I don't know any other method for testing them.

Computer Hardware

  • MSI P67A-C43 B3 Board
  • Intel Core i7-2600K
  • PNY 16GB DDR3 RAM Kit
  • MSI HD6770
  • DVD Writer
  • MSI NightHawk Mid Tower
  • DiabloTek 650W PSU
  • Additional PSU: Corsair – Gaming Series 700-Watt ATX CPU Power Supply

Best Answer

Possible causes:

12V CPU power connector to motherboard not connected.

Clear CMOS jumper missing (if required) or in incorrect position.

CPU fan not connected to proper header or CPU fan broken. (Not spinning, not reporting spinning to motherboard.)

CPU socket damaged due to fumbled CPU insertion.

Heat sink not properly mated to CPU.

CPU not supported by motherboard BIOS. (You need at least version 1.7)

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