Here is the proper link for HiJackThis version 2.0.4 Please uninstall that old one you have and download the new one.
The old one doesn't work properly with Vista.
http://free.antivirus.com/hijackthis/

ATI Cleaner is NOT the correct program. Here is the correct program it is ATF-Cleaner
http://www.atribune.org/index.php?op...d=25&Itemid=25

Please UNINSTALL Shareaza. P2P file sharing is very likely how you got infected in the first place.