problem with uninstall of Virus scan 11.1 for Mac

I'm trying to uninstall Virus Scan 11.1 from my husband's Macbook Pro.  As his computer is older, I can't just drag and drop it to the trash as I did with my computer.   The help menu says to type the admin name into the authenticate window, but I can't figure out where that is.  Do I really need to download the removal tool or is there an easier way?  He's running OS 10.6.8.