800$ first time builder help!

I installed everything correctly to my knowledge. On start up everything seems to run power wise, and the green led light comes on the mother board. But nothing on the screen. I attempted this because reading it looked simple and I have changed hardware before. Here is what I bought.

Motherboard: asus p5n-d socket 775

Ram: ocz technology ddr2 dual channel kit. 2 sticks@ 2g each

Case: cooler master chassis cm 690 socket 775

CPU: Intel core 2 quad processor freq:2.66gh core: 45nm fsb:1333mhz l2 cache 6 mb pcg:05a socket lga775

Power: ultra 750 watt atx

Graphics card: geforce 9500 gt pci-e 2.0 1gb ddr2

Hard drive: Sata wd caviar green 1 tb

Dvd Drive: sata


I am wondering if maybe something is not compatable here??? I read a lot and sure thought I did everthing correct??? The only thing is the case did not come with enough brass pins to screw in the motherboard??? I have them all in the correct spots under the motherboard, but there wasn't enough to screw in on top of the motherboard. Would this cause it not to boot? I am a newbie that probly should not have attempted this, but I love computers and wanted to learn how!!!! Is there a place I could call or take a home build into? Or is there someone in the metro detroit area that would be willing to help me for a cost???????????