Computer won't power up.

I'm having an issue with a computer I've recently been upgrading. I've started upgrading all of the obsolete 4 year old parts, so I've replaced the PSU, CPU, RAM, GPU and Mobo; however, when attempting to start the computer it powers up for a few moments and then shuts down. I've scanned the typical 'what do do if..' threads, followed their advice and still been plagued by the issue. I've tracked the problem to the CPU, by uninstalling everything except for Mobo, PSU, CPU and RAM. When the power button is pressed, the computer starts for a few seconds before shutting down. The CPU fan gives a few weak lurches before stopping. A few seconds later, the computer turns itself on, and then shuts down again. I'm fairly certain it's the CPU because the case fans and GPU fan all start spinning normally when plugged in.

For reference, my specs are as follows:

GIGABYTE GA-Z77MX-D3H LGA 1155 Intel Z77 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard

Intel Core i5-3450 Ivy Bridge 3.1GHz (3.5GHz Turbo) LGA 1155 77W Quad-Core Desktop Processor Intel HD Graphics 2500 BX80637I53450

SeaSonic M12II 620 Bronze 620W ATX12V V2.3 / EPS 12V V2.91 SLI Ready 80 PLUS BRONZE Certified Modular Active PFC Power Supply

Patriot Viper 3 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model PV38G160C9K

It's worth noting that this has been a test run on a new PC- I haven't connected an HDD yet. I know that I can't get past BIOS without a hard drive, but right now I can't even get TO BIOS because the computer shuts itself down.
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  1. ok try all of this if you can(any of the if possible ignore because you cant access your build
    1) Update bios(if possible)
    2) Clear Cmos, do this if you cant start or have messed with the bios (don’t forget to unplug the computer from the wall and let it sit for few minutes, if you don’t have a jumper than remove the battery make sure the computer is unplugged and let it for about10 minutes before putting the battery back in)
    3) Check your psu
    4) Make sure your computer is hooked up correctly
    5) Run memtest(if possible)
    6) Run Burnintest (if possible)
    7) If all else fails then try a gpu, Ram, or psu from another computer
    Hope this helped! :D

    im leaning more toward the psu as the issue but still perform anything from the list above you can do
  2. I forgot to mention that I had this issue with my previous PSU as well, and I am still having the same problem with the new one. So I don't think the PSU is to blame, since my previous PSU ran my previous computer just fine.

    My problem here is that the computer is literally only on for one, maybe two seconds. I can't do anything, and the motherboard has never successfully booted so I haven't been able to access BIOS. It's not even long enough for the motherboard speaker to beep.
  3. yeah have you tested your psu? i know it sounds weird but test it because that sounds exactly like if you had a bad psu... now if it passes it easily could also be the mobo... i think if the psu passes the test(in my previous post) then you will want to rma your mobo
  4. Just tested the PSU and it checked out. I'll do some more fiddling, then I'll send the mobo back and check the standoffs. They look slightly misaligned.
  5. ok sounds like a plan, also be sure to check the ram because it could also be that if you have any other ram to test put that in, if not then get that rma'd when you get your mobo rma'd(if you decide to)
  6. Hold on a second. I checked my Mobo's website. The RAM it came bundled with (combo sale on Newegg) doesn't fall under the supported RAM in the list. There's other Patriot RAM there, but not the specific model that's in my machine. Would Newegg really send me RAM with a motherboard that doesn't go together? :|
  7. seems that way... so then i recommend calling newegg and gettinga refund on the ram, what i dont understand is the ram is 240pin and is ddr3 how is that not compatible?
    well i mean i see what you mean its not on the support list but the other patriot ram is so im not sure if the ram is just not faulty
  8. This weekend I'm going to disassemble all the parts, ensure the mobo is seated correctly on the standoffs, and if it still doesn't work I'll RMA it. I just don't want to keep using this shoddy old Pentium 4 PC.. *shudder*
  9. Will be interested to see what your issue is- bc Im having same problem...on for 2 seconds off-- on 2 off- repeat...

    gb ga-z77x-d3h
    i5-3570k stock fan
    650w antec-- (tested ok in diff pc)
    crucial 12 gb pc1600 ram (tried 1 stick at a time)
    MSI 7770- tested ok
    corsair 600t case
  10. yeah it really sounds like a psu issue but because you already got it replaced it could just be faulty pins on the mobo, not that you can fix that only get it replaced
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