PC Won't Post

I have a home built Gigabyte GZ-x1 case,gigabyte 8knxp motherboard, p4 processor 2.6mhz 800fsb, 6 sticks of simpletech pc3200 ddr ram 512k each, lg dl dvd writer, lite-on dvd writer, 40gig hdd, 160gig hdd, 2x200 gig sata hdd, ati aiw 9600 pro graphics card.

I tried to start my pc one morning about 3 weeks ago now after a regular shut down the night before and since I can not even get pc to post. I have tried replacing cpu w/two different 3.4 mhz processors, ytried a new power supply even went so far as to try all these components with a new motherboard using all three diff spu's and each stick of memory seperately with just the basic minimum of components and still the same result from every thing. power comes on but does not sustain monitor or post. No result from pressing caps num lock or any key. I am just about to go out and buy a piece of crap if I can't find out what is wrong.