Computer won't turn on. Is my CPU dead?

[R3fa]

I recently purchased and setup a new gaming rig. It worked good for about 2 months then i had issues with it locking up while in windows. So i did a dirty shutdown one night and now she won't come back on. I just got my motherboard back from RMA (my first suspicion) i installed everything again, and it still won't turn on. I've tested my GPU in a different box and it works fine. How should i rule out the RAM? I've tried the usual steps, try 1 GPU, different slots, 1 stick of ram in the slot closest to the CPU, clear the CMOS, remove battery, unplug everything for 24 hours (drain all power). Nothing seems to work!

Here's the symptoms:
Everything is installed properly (i've checked 4 or 5 times)
1. I push the power button
2. All my fans spin including CPU fan
3. my monitor light just blinks
4. No BIOS and my comp just sits there.

Here's my setup (if it matters?)
AMD FX6100
G.SKILL Sniper series ddr3 18866 8gb (2x4gb)
Asus M5A99X
Rosewill 600W PSU
HIS 5770 x2 (crossfire)

 

[RealBeast]

I would use a multimeter and check the ATX12V and GPU power cables from the PSU. Then I would use a different single stick of RAM to see if it will boot.

If those are not the issue, I would pull the board from the case and build it on my desktop with a non-conductive top -- like a big sheet of cardboard. Only use a minimum of stuff on that build -- this will insure that you don't have a motherboard short to the case.

 

[R3fa]

I've sent my processor in for RMA.

When you say use a multimeter to check the ATX12V and the GPU power cables, what should I 'check' for? I've never used a multimeter on a computer before. What should they read?

A friend at work has a spare CPU (i'm going to try today) and see if it fixes my problem.

 

[RealBeast]

Black wires are ground, yellow are +12V, and red are +5V.

So on the ATX12V and 6/8 pin graphic card connectors using the black multimeter probe on the black ground wire and red multimeter probe on the yellow +12V wire you should read +12V on your meter. You can check each yellow 12V wire and ground wire. The alternative is having a spare power supply, which also tests your PSU, although indirectly.

The reason I mention testing the ATX12V and graphic 6/8 pin connectors is that the symptoms you have would result if one of those was not functioning. You fans would spin but no start-up.

 

[swoz]

When you say use a multimeter to check the ATX12V and the GPU power cables, what should I 'check' for? I've never used a multimeter on a computer before. What should they read?

With the multimeter, set it to measure resistance (Ohms) and look for shorts. If the resistance is less than about 5 Ohms across a rail to ground, or rail to rail, there is an issue.

 

[ram1009]

The suggested voltage checks are a good idea but must be performed under load. Beyond that the only option available to you is to replace components one at a time with known functioning equivalents or to place all of your suspect components in a functioning rig, again one at a time.

 

[R3fa]

So the voltage checks would do me no good in the current state of my machine?

I'll probably have a different processor to test later, but for now my FX6100 is going to RMA.

Do motherboards usually short out to a chasis? I've never really heard of that happeneing, or experienced it in all my builds.

 

[RealBeast]

Not terribly common, but I've seen it a couple times.

 

[R3fa]

Best answer selected by R3fa.