Or, before taking things out, we can do this the easy way.
Is the red light on your logic board on?
Try and locate the small button on your logic board, (its buy the big battery you see in there) and push it, now wait 10 minutes, and then try it.
Check and make sure everything is still seated correctly, your video card, ram, and processor.
The processors are extremely easy to remove, the heatsink comes off, and then there are 3 screws that keep it held down.
MacBook 2.16 Core 2 Duo, 2 gigs of ram, 120 gig hard drive Snow Leopard 10.6
PowerBook G4 15" High Res 1.67PPC, 2 gigs of ram 160 gig hard drive Leopard 10.5.8
HTC MyTouch 3G 4 Gigabytes Unlocked, Rooted 2.0 Eclair