If you are trying to turn off the Norton firewall in order to use OneCare, uninstall the Norton product and then use their cleanup tool -
ftp://ftp.symantec.com/public/english_us_canada/removal_tools/Norton_Removal_Tool.exe
If you are using Norton and need to know how to turn off or configure the firewall, you're off topic for this forum, which is for the discussion of Windows Live OneCare.
-steve