New build turns on then off within 2 seconds

I've looked around a lot to find an answer to this. I just built my first system, spent a good deal of time getting it wired correctly, and put together. I turned the power supply on, I heard the speakers make a crackling sound, the mouse lit up, psu fan turned on, case fans turned on and the memory LED on my motherboard. Within 2 seconds, everything but the speakers and mouse seemed to shut down, then about 8 seconds later, another crackling sound (which I assume is the speakers shutting off). The mouse somehow stayed on. Now I cant make everything turn on again for 2 seconds unless I shut the psu off, then turn it back on in 10 seconds. This all seems odd, and I've asked just about every tech savvy person I know, as well as searching the internet for similar problems.

I've gone through everything a couple of times, everything was wired correctly, I've tried turning it on with just the cpu, psu, ram, and motherboard installed, still get nothing but the same. Reset cmos, and a lot of other random attempts to trouble shoot this problem. All of the answers seem to be inconstant and i was just wondering if anyone has any ideas as to what else i can do to troubleshoot, I'd rather not have to RMA most of what I just bought, thanks for your time.

MSI 790FX-GD70 AM3 AMD 790FX ATX AMD Motherboard
VisionTek 900244 Radeon HD 4870 512MB
AMD Phenom II X3 720 2.8GHz Socket AM3 95W Triple-Core Black
G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600
NZXT Apollo Black SECC Steel Chassis ATX Mid Tower Computer Case
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  1. Hm the psu should definitely be strong enough, no problem there. Everything else looks great too the only thing I could emagine making trouble (except if something is really broken) are the ram. Officially phenom II only supports ddr3-1333 ram. It shouldn't have any problems with ddr3-1600 but still there's a danger.

    Try to boot with only one of the ram modules, if the system boots the motherboard/cpu combo have a problem with the ram. Upgrade to the latest bios and try again with both ram's inside..

    Hope I could help ypu
  2. Try using each stick of RAM separately. A computer I was working on a few days ago was doing something similar and it was a RAM issue.

    Edit: I guess Erdinger already suggested that, man it's early :(
  3. Nothing to do with the heatsink not sitting correctly and the CPU overheating and shutting down? They can get hot very fast. Just a thought.
  4. I actually just re-seated the cpu and heatsink, with a fresh coat of thermal compound so I think I've ruled that out. The ram doesnt seem to be it either, I've tried both sticks in several different slots, alone and together and still nothing. It's really starting to look like something is just defective, not sure what though.

    Thanks for the help so far though, appreciate it.
  5. Here are my "most likely" thoughts.
    1. The PSU may be defective, and it failed almost immediately after its first start-up. See if you can borrow a PSU to substitute for a test. For the minimal test with only mobo, CPU, 1 stick of RAM and video card, even a PSU with much lower output will do the job. (If you can, for testing like this don't even install the video card - use the mobo's built-in video if it has it.)
    2. You have a short from mobo to case. To check, remove the mobo etc from the case, set it on a non-conductive surface, and do the minimal-system test. If it works just fine outside the case, start looking for what is causing the short. One common cause is having an extra stand-off (for mounting the mobo in the case) in the wrong place so that it makes contact with the bottom of the mobo. There should be standoffs mounted in the case ONLY where they match up with mobo mounting holes.
    3. Check the way the CPU cooling fan is connected to the mobo pinout. Of course it needs to get power to run the fan, and I'm assuming you have verified that it does run. But in addition that connector feeds a fan speed signal back to the BIOS so it can check and be SURE the CPU cooling is working. If it does not get a fan speed signal, it will shut down quickly to protect the CPU from overheating.
    4. Even though you checked the heatsink and thermal paste, there is the possibility there is still trouble there. IF you put too much paste on it can actually interfere with heat flow and cooling, allowing the CPU to overheat. However, this is reaching! Even if this were the problem, I would expect it to take many seconds - like 15 to 60 or more, and certainly much more than 2! -for this to cause a shut-down from high CPU temperature.
  6. Thanks a lot everyone, the case has a few issues and wasn't grounding it properly, fixed that and seems to be working just fine now!
  7. Awesome. Enjoy your new build!
  8. good to hear that its working, I had trouble getting SLI running and there isn't anything more excruiation then a new build not working properly :D
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