ISA - Gator.com: Blocking Protocol

I had a similar problem and had to go to a tech rep at Gator to get the instructions on how to remove ALL components. Seems that Gator hides some stuff when it is installed and even if you uninstall Gator, that bit of code that lets Gator connect outside and lets advertisers send pop messages is still in your machine AND it's protected so you can't delete it. I HATE Gator. It's intrustive and compromises security by configuring open ports, even with ISA filters in place. Bad Doggy!

you might want to try both IP address and name filters. If that doesn't work, restrict user rights of those who insist on trying Gator and not allow them to install any program. They can still access the web, BUT they are not able to install programs.