I have XP as OS. Switched on computer couple of weeks ago, window came up telling me to uninstall NAV2004, and reinstall. I have tried to do this a number of times with no success. My system is doing the same actions as yours. I have tried to log on to the free e-mail help at Symantec, but have been unsuccessful. I don't want to try the pay help line, I purchased the AV2004 two months ago; and it has been working normally.
I am sorry I can't offer any solution to the problem, but thought it might help if you knew you were not alone.
Hoping that our good friends on the forum will come up with suggestions.