Open Norton and on the top row you should see the Help click this and the dates for the activation start and finish should show. if this is wrong you can have a good time getting that through to Symantec who are almost as bad as Microsoft an believing ther customers.
Uninstall it then go into the registry and search for any reference to "Symantec" then "Norton" "NDDS" "NDS" and remove go into your Documents and Settings/All users/Application data/ remove any Symantec or Norton folders.Then Documents and Settings/any named person/Application data/ remove any Symantec or Norton folders.
Then reinstall and start it up again,
there are a two or three removal tools on the symantec web site as well to try