two wires make up my (naked) power button on my PC. the 'button', if you want to call it that anymore, is not behind the conventional circular button anymore, but consists of two wires, a plastic casing that the two wires go into, and two copper-like metal above the two wires protruding out of the plastic casing.
here is a rough picture i just made in gimp, since i don't have a camera..
this is the 'thing' that the previously mentioned black box slides into..
i know this is a long shot. the model of the pc might help. it is a Sony Vaio, RS PCV-RS720G.
*edit* here is the black box in a little more detail: