Hello, I recently started playing GC2 again, and encountered a crash that was really annoying me. Everytime a combat sequence would start the game would crash back to the desktop. Well I thought that reinstalling would fix it like most other crashes for different games (or atleast in my case). When I put the 1st disk in I get an error message:

http://img153.imageshack.us/img153/5398/asdasdasdai9.png
Ive tried restarting, installing on a different account.
My CD has no scratches on it, and I havent downloaded any mods.
Any help would be appreciated, thanks.
EDIT: Ive also tried downloading it from Stardock Central. I have a serial number, but it keeps saying its invalid (ive triple checked it, everything is in order) I purchased my copy brand new from Bestbuy a few months ago