In short, no supported method is documented. In fact, with NAV being in it's current state, I wonder if you'll run into a "product activation" issue.
If you do and don't have time to deal with it, don't run without an Antivirus. Just fetch Free AVG from http://www.grisoft.com until you resolve the activation issue.
I'm builging a new PC to replace my aging PIII550 - fresh install of WinXp and Software to new hard drive.
Updating Norton after installing from scratch over my 56K modem (!!) will take an eternity (there have been many incremental updates over the last few months).......any suggestions? I've tried the Symantec web site and you can download AV IDE files but there are no program updates available...does Norton hide downloaded update files away somewhere or are they ditched on installation?