PC power/reset and maybe sleep and hibernation

Hey guys,

I was just wondering how I can replace a PC power/reset buttons with an arduino with touch shield to make an interactive button, but my main question is how can I do the hardware interface?

I found (link in next post since first post) but all it said was something about an optocoupler, what is an optocoupler and how does it work?

secondly I have experimented with Processing and communication with arduino and I was wondering if I can get the computer's sleep/hibernation functions through an arduino???

thankx for any insight...

here is the link:

Clicky...