Grif - theres new nonsense floating. People all over are getting those 'Congratulations you have been selected to win a free---" Wal mart gift card,nintendo wii etc,etc,..
Run a Hijackthis and see if you have Windows\system32\msziptools.dll
I also suggest running Malwarebytes' Anti-Malware
Once it guaranties the infected BHO's and Registry keys, delete them.