Hi there,
I have a Canon S2 IS and I would be happy to help out.
You are going to have to walk me through it as I'm not all that computer savvy.
I tried to load CHDK using STICK but got a message saying "No official build is available for this camera".
Here's some info I got on the camera using the Set/Disp hold down trick:
P-ID 30F0 NT
Firmware Ver GM1.00G
E18
Dec 19 2005
Cheers