I have a feeling you might be infected with the Vundo Trojan. Happened to me too...and I went here...
http://www.tech-forums.net/pc/f70/
And posted a Hijackthis log.
You can download the program here...
http://www.merijn.org/programs.php
Unless someone here might know how to read a log and tell you what to get rid off, and what to keep.