Computer won't power on -- Thoughts?

[sheriffbullock]

I purchased a new motherboard, CPU and RAM two weeks ago. Everything installed and ran smoothly for a week. A few days ago I installed the CPU cooler I had bought, a Cooler Master Seidon 120XL. The installation went well, and I had everything back in the case ready to fire up—only it didn't. My PC no longer powers up. For a brief second I see some blue LEDs illuminate and the fans spin, but then everything stops. (I hear no beeps from my speakers.)

I have:

- Checked, double checked, triple checked, quadruple checked the cables
- Looked under the motherboard for loose screws, cables or unnecessary standoffs (nothing)
- Replaced the PSU with a new 750W PSU (original was a 550W)
- Moved the RAM to the other slots, and tried booting with only one stick of RAM
- Uninstalled the CPU cooler and reinstalled the original CPU fan
- Looked for damage on the CPU (found some errant thermal paste, and gently wiped it off)
- Looked for bent pins in the CPU socket (there were none)
- Cleared the CMOS with the clear CMOS button
- Removed the battery for an hour to clear CMOS, then reinstalled it
- Looked for any signs of physical damage to the motherboard (no visible signs)
- Booted without the video card, and booted without the case
- Reconnected old PSU, motherboard/CPU/RAM, HDD and peripherals to my case—they all still function

I suspect the problem lies within the motherboard or CPU. Any suggestions on things to try before I RMA the motherboard? (And possibly the CPU? Should I RMA both?)

Specs:

Motherboard: MSI Z87 MPOWER LGA 1150 Intel
CPU: Intel Core i7-4770K Haswell 3.5GHz LGA 1150
RAM: G.SKILL Sniper Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1866
Video: AMD Radeon HD 6950
PSU: Corsair CSM Series CS750M 750W ATX12V v2.4
Cooler: Cooler Master Seidon 120XL
Case: Rosewill BLACKHAWK Gaming ATX Mid Tower

Thanks in advance for the help, everyone.

 

[danielmoore2276]

Unfortunately, with the information at hand, it's impossible to say for sure what happened. but the fact that it won't even boot up enough to give error beeps does suggest that power is not getting to or through the montherboard. It almost has to be a PSU failure or some part in the motherboard frying. If you want to diagnose further, a specialty computer parts store would sell PSU testers. The simple ones, which just plug into the PSU and have a few LEDs to indicate power flowing through them, usually only cost $10-15. Just make sure the one you buy has the correct plug design (check your computer's Owner's manual), as there have been a few different power connection designs on motherboards over the years.

As for a replacement power supply, that shouldn't be too bad.

 

[sheriffbullock]

Unfortunately, with the information at hand, it's impossible to say for sure what happened. but the fact that it won't even boot up enough to give error beeps does suggest that power is not getting to or through the montherboard. It almost has to be a PSU failure or some part in the motherboard frying. If you want to diagnose further, a specialty computer parts store would sell PSU testers. The simple ones, which just plug into the PSU and have a few LEDs to indicate power flowing through them, usually only cost $10-15. Just make sure the one you buy has the correct plug design (check your computer's Owner's manual), as there have been a few different power connection designs on motherboards over the years.

As for a replacement power supply, that shouldn't be too bad.

Unfortunately, with the information at hand, it's impossible to say for sure what happened. but the fact that it won't even boot up enough to give error beeps does suggest that power is not getting to or through the montherboard. It almost has to be a PSU failure or some part in the motherboard frying. If you want to diagnose further, a specialty computer parts store would sell PSU testers. The simple ones, which just plug into the PSU and have a few LEDs to indicate power flowing through them, usually only cost $10-15. Just make sure the one you buy has the correct plug design (check your computer's Owner's manual), as there have been a few different power connection designs on motherboards over the years.

As for a replacement power supply, that shouldn't be too bad.

I doubt it's the PSU because I tried the board with a 550W and a brand new 750W.

Originally I had installed the CPU cooler with the 550W and thought maybe the pump, mobo, CPU, video, etc. was too much for the PSU and fried it. But, that turned out to not be true because I've put all my old equipment (including the 550W PSU) back in my case and I'm using it now without issue.