MSI P55-GD55 will not turn on, don't think it is PSU, Any Thoughts

Motherboard P55-GD55 i7 12gb ram, Win 7

Power supply 1: OCZ Stealth Stream 600w
Replaced w/ PS 2: Antec Earthwatts 500W 80Plus


I'd appreciate any thoughts of what might be wrong.

Firstly, a couple months ago, i would get a random shutdown. I monitored Core temps, and discovered the paste had worn away. I repasted the fan to the CPU. Temps were fine.

This system runs mostly 24/7.
I had an experience a couple weeks ago, the system would not turn on. No fans or lights. I thought it might be the PSU (OCZ Stealth Stream 600w). I had a new one *(Antec Earthwatts 500W 80Plus) that I plugged in and everything worked.

Thinking I was brilliant solving this problem, everything ran fine until today. I did a shut down to install another SATA drive. (If it makes a difference the box is filled, 2 SSDs, CD rom, and 3 SATA HDDs).

Now the computer will not start at all. Again. So I thought it may not have been the PSU. So I swopped the first one in and it worked!!! Now to get my drives plugged in again. Shutdown. Added a drive or two, Kind of worked. Then again completely dead.

The likelihood both PSUs were bad? In the process I think i fried a HDD with the SATA Power cable. How sensitive is the PSU? if there is a bad HDD would that prevent it from turning on?

So, just now i try again with just the single SSD startup drive and CD. Started twice, I'm watching CORE TEMP, everything looks good 50c to low 60c

I know I can run this for a couple days and then need to shutdown to add a drive and it will not start?

All power plugs to the MB are in firm. Ram in tight. Fans blowing. Video card well seated.

Problem is, I do need to add those other drives eventually. Too afraid to shut down now.

Any diagnosis?

Could hooking up a bad SATA HDD, somehow Trip something in the PSU or motherboard?



Can't really afford a new system now. What else can cause the computer not to turn on at all? I will try to swop back to the original PSU.
Everything is plugged in Mother board and that extra 4 pin. Two PCIe to the video card. for now just the two SSDs. and the CDROM.
6 answers Last reply Best Answer
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  1. Ok here is something to try. Put in your OCZ power supply and make sure the ATX power switch is turned off and that the unit is unplugged. Then hook up all of your drives like they were before (I have never seen a bad drive prevent powering up but i have seen them lock up the system on start up and at the BIOS screen).

    Now plug in the power supply and turn on the ATX power switch once again and see if the machine will boot.

    Please let me know what happens.
  2. At the moment it is running with the single SSD and an external USB HD. Years ago My Mac II, would not start and it turned out to be a battery, which a repair place charged me $100 to replace. Those computers used a keyboard to boot.

    The only battery iI see is for the CMOS. other than a clock, is it used to turn on the PSU?

    I want to isolate the problem. Its running now, but i guess if i shut down it could be dead again.

    Core Temp shows id 40c now, so i don't think the CPU is overheating.
  3. Just a thought. Say it was the switch on the case. Is there an on board way to turn on the computer? Just trying to eliminate variables.
  4. You can try replacing the CMOS battery with a new one (it's very cheap).
    For starting the board without using the switch, remove the wires that go to the power button and use a screwdriver for shorting the 2 pins on the motherboard where the wires were connected (it's what the button does when pressed).
  5. Is the switch an on/off or momentary? If I just trigger is as you said, will it remain on or will the PSU turn back off?
  6. Best answer
    It's momentary. You just shortly touch for sending the signal to the PSU, then remove the screwdriver.
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