Try uninstalling and then re-installing your Norton Anti-Virus. Seriously. =)

If it doesn't work though, then you could uninstall it again, delete any keys relating to Norton from your registry, then re-install it, and it will work, but it's never a good idea to go poking in your registry unless you know what your doing. =)

Or you could go buy a copy of Norton AV 2003, since 2004 is out PC shops are liquidating their 2003 copies at about $35 CAD a shot.

A+ Certified PC Tech Guy/Seitentaisei