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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 (http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems). 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.

Questions

  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
  • OCZ SSD
  • DVD Writer
  • MSI NightHawk Mid Tower
  • DiabloTek 650W PSU
  • Additional PSU: Corsair - Gaming Series 700-Watt ATX CPU Power Supply
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try a different brand of ram. –  Moab Feb 3 '12 at 0:05
    
Two power supplies? –  Canadian Luke Feb 3 '12 at 0:25
    
@Luke I bought a second power supply to verify that the PSU was not the cause. –  Castrona Feb 3 '12 at 3:28

5 Answers 5

up vote 3 down vote accepted

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)

share|improve this answer
    
I made sure that the 12V power connector is connected. I've tried clearing CMOS by placing the jumper on pins 2-3. I've also tried removing the battery. Neither of these have fixed the problem. The CPU fan does spin (albeit briefly), and is plugged into to proper connection on the motherboard. I was very careful placing the CPU in the socket, and I've inspected the pins. Nothing seems to be bent. I bought these parts as a barebones kit, so I assumed that the CPU was supported by the BIOS. Is there any way that I can easily check this? –  Castrona Feb 3 '12 at 3:33
    
The CPU fan will still spin up if the sense wire is open circuit. –  Tog Feb 3 '12 at 9:00
    
@Tog Is it common for CPU fans to not work? I got a replacement i7 CPU (and stock fan), but have the same problem. B/c of this, I am thinking that the CPU and its fan are not the cause. Is it incorrect to assume this? –  Castrona Feb 3 '12 at 18:10
    
@David I checked the MSI website and verified that the motherboard supports my CPU. Also, how can I tell if the CPU fan is not reporting to the motherboard. This is my second stock CPU fan since b/c received a replacement CPU. Is it possible that the CPU fan doesn't work with this motherboard? I guess I could go buy different one and try it out. –  Castrona Feb 3 '12 at 18:15
    
The motherboard supports your CPU with BIOS 1.7 and later. If you have an earlier BIOS version, it doesn't support your CPU without a BIOS upgrade. It's not possible for the CPU fan not to work with the motherboard. –  David Schwartz Feb 3 '12 at 19:58

guys! Sounds like You've stumbled with this MB and new processors? Well, I had faced a same problem today and successfully solved it. MB MSI P67-C43 B3 + CPU i5-3470. It started with 4 (!) beeps, telling, I guess, faulty MB, but digging some answers, I just updated BIOS to the last version on the official site, that was confirmed to work with this new technology. I had to run update on a CPU that was supported by that BIOS from Windows. Unfortunately, there is no chance to upgrade Your BIOS if You don't have other compatible CPU. So, wish You all good luck and look for info on the official site - google help You! ;)

share|improve this answer

Does the fan start spinning, then stop and continues to cycle like that?

Motherboard is the most likely culprit, and it was our problem, but since you've replaced that along with the PSU and CPU, I would actually try a new CPU fan.

I wouldn't think the GPU would cause this, though I guess it's conceivable.

share|improve this answer
    
I'm using the stock CPU fan, that comes with the i7. The CPU cannot be overheating, b/c the power only stays on for a few seconds. I assume that the stock CPU fan would work at least well enough to enter BIOS. –  Castrona Feb 3 '12 at 3:34
    
The CPU fan starts spinning, then all power turns off. This cycle continues. I'm using the CPU fan that came with the i7, is this bad? Is it possible that the stock CPU fan doesn't work with this motherboard? –  Castrona Feb 3 '12 at 18:29

I have the exact same computer with the exact same problem. I found that if I only use a particular two of my 4 sticks of RAM in slots 1 and 3 it will work. Any attempt to install the other two cause it to cycle off and on.

I took the two suspected bad RAM sticks to my home machine (same motherboard and processor) and when I put them in it did the same off/on cycling so I'm fairly confident the issue (which is identical to the one you described) is bad RAM.

I'll edit this post later to let you know if replacement RAM entirely fixes the issue.

share|improve this answer
    
Well, probably cause it may be seen as not being an answer - it might work better as a comment, unless of course, your ram fixed it, in which case it might be an answer. Q&A dosen't quite work the same way a forum does –  Journeyman Geek Feb 14 '12 at 12:57
    
My apologies. I didn't play close attention to the answer vs comment distinction. Let me find a way to move this one to a comment. Hey Journeyman, How do I add a comment? Only spot I see is on this post. –  gatsby Feb 14 '12 at 13:06
    
@gatsby Super User requires a reputation score of at least 50 to get the privilege to comment everywhere (note that you can always comment on your own posts and on answers to your own questions), so get a few upvotes and commenting everywhere will be yours. –  DMA57361 Feb 14 '12 at 16:26

Could be either the Motherboard or The RAM. try using only one stick of RAM and see what happens. Sometimes the speed of the RAM (if its set to high) will prevent the system from booting. There also may be some difference in the CPU (the type of bridge) that you need to consider to use a particular type and speed of RAM.

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