trouble uninstalling old fragments of Internet Security

I'm running an early 2008 Macbook and recently had to install a new hard drive.  I didn't have the apps backed up to save space on my external drive.  When I restored my partial backup, it apparently included some of the previous Internet Security install. Now when I try to install a fresh copy of Internet Security it says I can't because "the following incompatible product(s) are already installed: Norton Internet Security."  Internet Security doesn't appear in the Applications list in Finder.  I'm not sure where to look for the rogue pieces to delete.  Any thoughts?  Thanks, in advance.