Originally Posted by Bigjohn

Try using system restore.

If that doesn't work, go into safe mode and use spybot in the advanced mode. Look at BHO (Browser helpers) and active X. Delete/disable anything you don't recognize.

Make sure all of your search/home page settings are set to Microsoft defaults (you can use MS antispyware to do this).

So far this has worked for me everytime. It does leave some of the files on your HD but since nothing is pointing to them anymroe it doesn't matter.