NIS 2003 gave me numerous networking problems until I finally ditched it. I don't remember, but I believe norton itself asks whether you want to password protect some of its functions, so I don't know whether or not logging in as an admin in windows will matter; you might have to start norton itself as a privelaged user (password-prompted, maybe??)
Anyway, there are lots of threads on the topic for free firewalls and av. Currently, I use avg for av and sygate for my fw. I have found the sygate to be configurable enough for me, and it has given me no problems (unlike norton) and avg updates almost daily, and very quickly when responding to new threats.