Dear Forum,
My new i5 2500K build won't power up. I am using a Gigabyte GA-Z68M-D2H board with a RoseWill 400 Watt Power Supply. When I press the power button, the power LED lights for a second or two, and the cpu fan turns on for that period, then they stop. I read somewhere that I need a 500 Watt or GREATER power supply. Is this a symptom of that?
Thanks!
Mike
 I'll assume this is your self built...
Did you apply thermal compound when assembling the CPU/heatsink assembly ?
Are all MBoard standoffs in place ? ?
Did the PSU have the additional 4/6 pin CPU power plug ? ?as far as i can remember, the i5 systems are recommended at least 600w. i am building an i7 self build, and have gotten a 700w to be safe, taking into account that I might be adding a 2nd HIGH powered graphics card in the future.
i'd recommend trying a higher powered psu.Hi Guys!
Thanks for the help. I checked the PS pins to gnd, and they seem to have a good ohmage value (not grounded), so I think the board is installed in the chasis OK.
I then unplugged everything but the 24 pin and 4 pin ATX connectors. I also unplugged one of the two RAM  sticks. It did the same thing. Power LED lights for ~1.5 seconds instead of ~1.0 second.
I then upplugged all plugs, shorted 15 to 16 on 24 pin, and powered up. The fan runs constantly, and all voltages appear normal, except the -12V measures -11.0V. I found a chart that says this should be OK, however; UNLESS it is going LOWER on load? (chart says limit is -10.8V) What is the -12V used for?
Thanks for your help!
MikeUpdate: I removed the board and powered up. It works! Must be something shorting out. I'll probably try a sheet of mylar under.
Thanks!
Mike
 I was thinking it was the motherboard mounted to the case as well.  Make very sure you don't have a stray standoff in place, as that touching a resistor or any other part of metal trace will ground the wrong part of the board to the case and cause a short.  I've had this in the past, I had forgotten to count all my standoffs and make sure I had the same ones lined up.  My motherboard would not start unless it was pushed in this one spot, which is where the standoff was that shouldn't have been there.  It was frustrating, but a relief when I found this out.