Go get <a href="http://security.kolla.de/">Spyware Search and Destroy</a> and scan your system.
Then, go get <a href="http://www.javacoolsoftware.com/spywareblaster.html">SpywareBlaster</a>, which prevents some of this stuff from being loaded in the first place.
Since installing SpywareBlaster, I have yet to receive one pop-up of Gator wanting to install.