Please Help!!! gaming pc will not start up!

[GaryAir]

A few weeks ago I had built my first gaming pc with my friend, he had mainly built it. When I go to start it up now it will power for a second then shut off, please help!!

Build

I5 3570k
Gtx 660
8gb ram
As rock pro 3

 

[GaryAir]

The pc now starts up but there is no signal all plugs are in properly running an hdmi from my pc to a tv

 

[GaryAir]

Super old post, but the problem was the 24-Pin not being fully secured in the motherboard.