New Home Built Computer Won't Turn On

[megabattle]

I just built a computer with these specs:
Intel Core i5-2400 Sandy Bridge 3.1GHz CPU
GIGABYTE GA-Z77-D3H ATX Intel Motherboard
EVGA GeForce GTX550Ti 1GBDDR5 Video Card
Western Digital 500GB 7200RPM Bare Hard Drive
ASUS Optical Drive
(was going to put on Windows 7 Home 64Bit OEM)
I bought all of the parts from newegg, and my friend and I built the computers in about 4 hours, because this is my first computer that I've built. After it was built, we tried turning it on and nothing started. We then spent the next couple of hours and days trying different methods and tips from sites. Can anybody give me any suggestions?

 

[rwayne]

What tips have you attempted so far?

 

[smorizio]

on the mb near the cpu did you plug in the 4 pin power plug that needed for the pci bus and cpu?? did you try and see if the mb will post on top of a box outside the case?? to make sure your not shorting it out on a stand off or the i\o shield??if the mb has some diag led for power and post are any of them on??? you need good power to have the mb post. if the fans dont come on it could be a power issue. also check the ram you have make sure it for the intel 2 gen or newer mb most of that ram is 1.5v. having to wrong ram the mb will power on but not post.also i seen dead ram from a ram kit. try one stick of ram in all the ram slots. if your cpu has built in gpu pull the 550ti and try and see if the onboard video comes on. look on the video card..ram and mb for any missing parts or damage. sometimes in chipping things get damaged. most times is a small cap that gets ripped off the mb. for the mb itself check under the cpu for any bent pins. those black cpu shields dont work to well there been posting on you tube of people getting new mb with bent pins. also check that you put the cpu in the right way..on thing that also will not let a mb post is if your missing the cmos jumper or it on the wrong pins. or the case header wires are on wrong. check also all the sata power and data that you did not snap or bend any of the pins.