Computer will not turn on/power up after crash during light use.

[Awsum McPossum]

This is a bit lengthy but please bear with me I want to make sure you guys have a full understanding of the problem in order to be able to help me.

Problem: Last night I was using my Desktop computer for the first time since May (I was working in an area where it did not make sense to bring a full desktop for the summer). It was working fine and dandy for approx. 1-2 hours, during which I was installing some of the latest updates for my games. I was flipping through the BF3 Premium webpage when all of a sudden my monitor went blank and then displayed "NO INPUT DETECTED". I have a Cooler Master HAF 922 Mid Tower Computer Case which has a known issue with the reset switch and the front USB ports and used to do something similar before I corrected it so I assumed it was something like that. I hit the Power button and held it down but the PC would not power off and I was forced to just unplug the PSU. Upon plugging it back in and pressing the power switch I can no longer get the PC to turn on. My mobo has a green led, called the "STANDBY POWER LED" in the user manual, that is on when I turn the power supply switch on but other than that no signs of life.

Specs of my PC:
Mobo: ASUS M4A89GTD PRO
CPU: AMD Phenom II x4 970 Black Edition
RAM: G.SKILL Ripjaws Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1333 (PC3 10666)
VIDEO: ASUS HD Radeon 6870 1GB
CPU COOLER: Xigmatek Gaia SD1283, NOT STOCK
POWER SUPPLY: CORSAIR CMPSU-750TX 750W ATX12V v2.2
HARD DRIVE: Western Digital Caviar Black WD1002FAEX 1TB 7200 RPM 64MB Cache and a second 500GB one I gutted from an external HD that's case broke
OS: Windows 7 Professional
CASE: Cooler Master HAF 922 Mid Tower

Things I have checked already that have not fixed the problem:
1. Ensured all cables were tight and seated properly (since I carried it around recently)
2. Visual check of the mobo for blown capacitors or anything else looking out of the ordinary (nothing found)
3. Set the Mobo up outside the case to make sure it is not a short from installation causing the problem. I currently have it sitting on the mobo box with the CPU, heatsink, and 1 4GB RAM stick attached, and the mobo and cpu plugged in to the PSU. When attempting to boot it from this setup I still can't get it to start. (tried both case on/off switch and using a flathead screwdriver)
4. Same as above but without RAM inserted checking to see if I can get a beep from the speaker. Nothing happens.
5. Resetting the Bios by removing the Mobo battery (mine does not have a jumper)

Anyways I am kind of at my wits end, since this build is a little under 2 years old and I was working properly less than 12 hours ago. I suspect it is from either the Mobo or PSU since it won't even turn on but I have no idea since the standby light on the motherboard is on indicating it is recieveing power but there are no visual problems that I can see. Since I am kind of a newbie at troubleshooting homebrews I'd appreciate any help/suggestions you guys could give me. Thanks!

 

[Awsum McPossum]

Small update: just ran the so called "paper clip" test and the psu doesn't power up (case fans are also directly plugged in to the PSU. is this indicative that it is indeed a power supply failure?

 

[Onus]

If the paperclip test also failed, it may very well be that your otherwise excellent PSU has failed.
With your current system, unless you're planning to add a second video card, or install something much more powerful, a quality 500W replacement would be sufficient. Seasonic, Antec, XFX, FSP, and Enermax/LEPA are among the better brands. Corsair may still be too, although their "Builder" units are now made by Channel Well instead of Seasonic.

 

[Awsum McPossum]

Thanks for the advice jtt283!
I built this PC with graphics expansion in mind (which is why i got the beefy power supply) so I think I will try my luck at RMAing it since it has a warranty of 60 months, but I will definitely look into those brands if they will not replace it. Thanks again!

 

[Awsum McPossum]

Best answer selected by Awsum McPossum.

 

[Onus]

Thanks, hopefully a replacement will solve this problem. I'm not sure what else it could be.

 

[Awsum McPossum]

Final update guys just in case someone has similar problems in the future. It was indeed the PSU unit. RMA'd the part and got a new one from corsair. Installed the new PSU and the computer booted up just fine. Thanks again!

Advice to anyone who has similar problems, make sure you do the paperclip test first (http://dodji.seketeli.com/downloads/shuttle-psu-paper-clip-test.pdf) to see if it is your PSU. It will save you loads of trouble if it is.