Yea, I know what your going through... One of my friends had more trojans than a college stud on her computer... :P It was a big hassle... On top of that... she had 3 viri on her computer too :S Can you say "messed up!" lol! Turns out her bro likes surfing porn sites and chatting on irc... Those are 2 red flags :) lol... Anyways, I hope ya fix it soon... Best of luck :)
Sorry it didn't work. As a last shot, could you post the log from Hijack This...................I might be able to recognise the problem. Also, go back to the SpyBot S&D site and get the special tool for a particular family of scumware that the standard version does not always catch..........sorry I cannot remember its name.
If you have to re-install (that IS the safest option) please get the utilities mentioned, as a lot of them will protect you in future.