Maximum PC

So my desktop computer is about a year old. About 3 months ago it broke, when I tried to turn it on the fans spun for a few seconds and then it shut off. I haven't really had time to try and fix it until now. It's a i5-2500k system, with ASUS P8P67 Rev 3.0 mobo, Corsair 750TXV2 psu, XFX 6950 1GB, 4x4GB G.Skill Ripjaws DDR3-1600 memory, and an OCZ Agility 3 120GB SSD. There's also a couple of SATA cards and a buttload of HDD's.

Now, what happens when I try to boot is that nothing at all happens. Occasionally the fans may attempt to spin for a fraction of a second and then stop. Only the green light on the mobo indicating that it's receiving power is lighting up, nothing else. So far, I've replaced the case (a P180) with a new Cooler Master Trooper. It was on sale at newegg and it was time for a newer, better case anyway. That hasn't helped. I have a Seasonic S12 500w psu that I've hooked up, just the 24 pin, 8 pin, and 2x6 pin in the video card; with that connected the psu fan and cpu fan actually turn but nothing else happens to indicate that it's booting. I've switched the video card with an old 7600GT and that didn't help either. I've also cleared the cmos.

Only the essentials are plugged in, the video card, 24 pin power, 8 pin power, 2x6 pin power, one cpu fan, and the 2 front panel switches and hdd led. Only one memory module is installed in the correct slot, I've tried different modules, and it still doesn't work. At this point, it seems very likely that the problem is the motherboard. What do you guys think? Is there anything I've missed that I could try?

How many hard drives and optical drives do you have in this system? If you have more than six of them, you probably damaged the motherboard by not using a power supply that was capable of providing enough power to it. ASUS provides a wonderful calculator for determining the minimum recommended power supply needed based on the hardware you have installed on it and it is here: http://support.asus.com/powersupply.aspx

It was 10 hard drives and one DVD drive. About half of them are low rpm green drives. I figured a good 750W psu like the TX750 V2 would have been able to handle that. Plus, it still doesn't work with my Seasonic psu and no drives.

Edit: The psu has a single 60A +12V rail. Seems like that should have been fine.

Nevertheless, all hardware has limits (including PSUs). I have personally seen motherboards damaged from using a power supply that was not able to supply the necessary power for all the hardware that is installed in a computer. I have also seen an ASUS motherboard damaged due to a failing chassis exhaust fan. Despite the fact that your drives are advertised as being "green", and that your PSU is a Corsair (an excellent choice, BTW) with a 12V rail rated for 60A, it always pays to give yourself some headroom in the choice of a power supply in the way of both quality and wattage.

Give the psu a sniff test to see if you can smell if it is burnt inside.

Is the cpu cooler seated properly...it may have come loose.

Call the motherboard manufacture and see what they say.

Nasty

No mention of a POST beep... Is there even that? If there's no POST beep, then something is really wrong.

Nope no post beep.

something to think about. if not now for the future. http://www.highpoint-tech.com/PDF/Staggered_Drive_Spin_Up-A_Primer.pdf

I just checked the psu and it doesn't look or smell out of the ordinary at all. I ordered an ASRock P77 Extreme4 that Newegg had on sale for $115 plus I got a Kill a watt meter. I've been looking up what HDD's draw on spin up, looking at max load values for similar machines here http://www.overclock.net/t/1126863/real-world-power-usage-user-submitted-values, and looking at what other people with many hdd's have and recommend for psu's and it seems this TX750 should hold up just fine unless it's faulty. I have heard of staggered spin up, but those controller cards are really expensive and the drives have to support it too, seems pretty tricky to get working. When I get the new mobo I'm going to check how much the extra drives affect power usage on startup. I have a new 3TB WD green which is going to replace 2-3 more power hungry old drives, so the HDD's won't be pulling as much power as they have been.

Keep us posted on the results using the new board.

Nasty

It's gonna be delivered tonight. I figure if it works I can RMA the old board and sell the replacement.