Deleting Gator

I have a computer with Windows 2000 Professional. A student downloaded Gator/Precision Time/Date Manager (all of these are related). I have run the uninstall and deleted the files from the hard drive. I have also edited the registry to what I think is all references to Gator. For some reason, Gator.com keeps returning to the registry. How can I keep it out of the registry permanently?