Hey guys,

My ex-roommate did some crazy things with my pc before he left
(yea we didn't end up on good terms) Anyway, he installed some software that runs in the background and tracks all my AIM, Yahoo and Msn conversations. I am not sure what software it is though, can you guys help me get rid of it? I can post by hijackthis log here if you want it...

And I know this sounds like a dumb problem but I don't want to format my system either; I have a lot of important data saved.
Will appreciate any help..