Use NOD32 and Kaspersky to eliminate the virus/trojans horses, then ad-aware and spybot S&D to do the same with spywares and malware and then Agnitum Outpost Firewall that can scan too. (all of them in their latest versions and updated) and you will get ride of all the crap, of course disconnect phisically of the internet hookup, reinstall nero and make your backups in dvds and then do a low level format because some viruses copy themselfs in the bootcamp. After reinstall use emule and utorrent as your p2p programs.
Sorry for my bad english.
Edit: I forgot, desactivate windows restore system and reboot, before the operating system loads press F8 to enter in boot options and select the secure mode or something like that and then scan, that´s because the restore system might replace the cleaned flies with the infected ones, and the secure mode because only the necesary drivers and system files are loaded so the security programs can clean the computer without problems due to "can´t overwrite file because it´s beeing used".