I don't know where my power switch plugs in on my mobo!!!

I can't find a manual or anything that tells me exactly where to plug in my power switch (to turn on my computer) into my mobo.

Here's my motherboard; the intel model D815EEA for PIII: PICTURE

somebody please help me, I have tried all of the plugs that looked like they were for it but none worked

That row of 16 pins (8x2) up near the top right of the picture you linked to should be the FP (front panel) connector bank. Your power switch should plug in there, where two of the pins should be labled PWR_SW or something similar. You might have to play with the polarity of the plug to get in to work.

Alternativey, while you are experimenting, you can just short the two power pins to send a power on or power off signal to the motherboard. I use the blade of a small screwdriver.