Fans and LED's turn on, no post, no beeps, no nothing

[whamajama]

Hi, I built my PC about 7-8 months ago, and until now it has worked perfectly, nothing major has gone wrong. Yesterday, my PC wouldn't boot, so I opened it up and didn't see anything wrong, Dr. Debug on my MoBo displayed "00" which normally means everything is running as usual. Basically, when I hit the power button, the fans whir up, the HDD's start spinning, all the LED's on both the case and the fans start up, but there is no display, no POST, no beeps, no audio, mouse and keyboard lights don't turn on, nothing at all. Here are the system specs:
i5 2500k CPU, not OCed
EVGA GTX 550 Ti video card
8 GB DDR3 RAM
AsRock Z68 extreme 3 gen 3 motherboard
500 GB 7200 RPM Western digital HDD (not sure on the exact model, I can figure it out)
500W Silver Stone PSU

I have tried the following to remedy these problems (to no avail):
Clearing CMOS, by hitting the button on the MoBo, removing the battery, and shorting the jumper
Swapping the RAM for some that I know is good
Swapping the video card for an even smaller one that I know works fine
Building only the core components (MoBo, CPU, 1 stick of RAM, GPU, and the PSU) on the box the MoBo came in
Reseating the RAM, GPU, and CPU
Making sure all connections are how they should be

I believe the following to be true:
The HDD is not the problem, considering removing it made no impact
Neither monitor nor the GPU are the problem, if they were I would hear the Windows startup sound
The RAM is not the problem, switching it out for sticks known to be good changed nothing

So that leaves the CPU, MoBo, and PSU. However, I have no idea how to test any of these...it seems like it isn't the PSU, considering all the fans and LED's start up fine. However, I have no idea how to figure out what the real culprit is...any suggestions would be welcome. Thanks in advance.

 

[johnb35]

I would guess motherboard before processor. Processor's hardly ever go bad. Can you test the processor in another motherboard like a friends maybe? If it works then you know its motherboard or psu. And if you try a different psu in your system and it still don't work then its motherboard.

 

[whamajama]

Thanks for the response, unfortunately I have no friends, so isn't an option, but tomorrow I may be able to use my parents' computer to test the processor, I will post the results of that, but in the meantime, what could have caused this problem? Overnight, nothing had changed in the computer, to my knowledge nobody even touched it...so what would randomly cause a motherboard to go bad? Regardless, if it were the PSU, wouldn't the fans/LED's not light up, or am I not really understanding the way it works?

 

[johnb35]

Motherboards can go bad at any time. I had one go out, was working fine the last time I used it and go to turn it on and nothing. Also, power surges, storms.

You've already done some diagnosing, you'll just have to go part by part until you figure it out. Every failure is different.