"Cannot start service"

When I attempt to install Norton Antivirus Corp 8.1 on a few XP machines at work I get an error message once the install is nearly complete saying that I do not have sufficient permissions to start the NAVCE service. However I am logged in as an administra
tor and I can start and stop other services just fine. The program is done installing at this point (I know because I can run the program from the start menu or the executable and everything works) but since the service won't start it rolls back the instal
lation and completely unistalls the program. This happens specifically after I have unistalled McAfee and its complimentary EPO loader. Is there some remant of the previous AV software that tricks the computer into thinking that my account does not have pe
rmission to start services (only specifically the NAVCE service)?

Thanks for any help