Window98 and NAV, password problem

I have a user on win98 and Norton anti-virus 5.0. For some reason when she tries to go into the options part (like to change from system files to all files) it asks for a password. She has tried all her passwords and none of them work. Inside ofthe options part there is a tab for password settings and it is checked, but greyed out so we cannot uncheck it. I have unistalled and reistalled and still have the problem. I install many computers here and have never had this come up before. I have also asked many of my co-workers and none of them have seen it as well.