Computer wont start, LED's flash for spit second.

[PCGamerKyle]

Edit: Wow, nevermind, I had the motherboard screwed in too tight, or something, I just unscrewed everything, and turned it on. it worked.

Hey, so I built my second computer awhile ago, and, I'm here because it wasn't working... I'm kind of a noob at this still, just giving a heads up, but anyways:

So, it was built, everything connected properly, I press the power button, all the LED's, and fans flicker for less than a second, and it's off. If I unplug the power cord, wait a few second, and plug it back in, it does the same thing. It's a 24 Pin connected motherboard, and then it has an ATX 12V, 4 or 8 pin. I tried it both, in 4, and 8 pins, and I completely removed the 8 pin, and same thing. So, I unplugged everything accept the Case's connectors, the power supply, the motherboard, and processor. Same thing. No beeps from the little speaker. I've tried a different power supply, same thing. But I never tested the other power supply before (came free with a case.)

Here's the parts (that are plugged in)

Motherboard: ASRock M3A770DE
CPU: Phenom II X4 955 Black Edition
Power Supply: hec X-Power Pro 600
Case: XION Solaris XON-403

 

[jsc]

The 4/8 pin PSU plug needs to be installed. That powers the CPU. Without it, you have no beeps. Use the 8 pin plug if possible.

Our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems

Silence with only the PSU, motherboard, CPU & HSF, and system speaker installed indicated a problem with the PSU, motherboard or CPU. Or something improperly installed causing a short.

Breadboarding:
http://www.tomshardware.com/forum/262730-31-breadboarding
is a good way to eliminate that possibility.