I have been wrestling with this for days now.

I have reduced the number of components plugged into my P4PE MB to a 2.4GHz Intel CPU, 1 512MB DS DRAM (SamSung) and all power supply connections and connections from the case have been quadruple checked. The Green LED is lit immediately after flicking the switch on the power supply (400W). I flick the switch on the case and the fan on the CPU spins for about a second and that's it. No fans, No power supply fans spin up, No beeps from the speaker -- nothing.

Is this a bad Motherboard? Bad Power Supply? Bad jumper setting somewhere?

thanks for any help !!!!!

Try using the cmos jumper or remove the battery for a few seconds. I would also remove the board in case it's grounding against something in the case, and try just one stick of ram, video card, and the cpu/heatsink on the static bag the board came in and see if it posts.

That one is easy.
Allready happend to me when i bought a P4S8X and DDR400 memory from samsung. The thing is that the board recognizes the ram with auto settings and that chipset you are using only has DDR333 support.
Youll just need to restart 3 times so that the board enters automaticly in the bios and there you can set the memory bus to 166.

Are you sure you have a AGP 4X/8X video card?