I had a similiar problem....make sure none of the socket pins are even slightly bent...it may very well cause that problem...if any are bent just take a led pencil with no led and bend them back, gently.
Hey Shum thanks for the heads up man. That's okay. I think I've come to the point of frustration that I think I'm just gonna take it into a shop and see what's wrong with this darned thing. I can't seem to fix it this time around.
Problem fixed guys! Thanks for all the help! Turns out it was a build up of dust behind the motherboard...first time didn't do anything, but after spraying very carefully at the spots that had more dust, I was able to boot.