First of all Norton Antivirus won't be able to remove maskrider.vbs.
Install Kaspersky Antivirus(the 30 day demo version will do) and do a thorough scan of your system
Clean all traces of the virus.
Now search your system for this file: Autorun.inf/autorun.ini and delete all of it.
You can unhide system files from the folder options menu and manually delete them too.
Your system will be ok.