I hope you have both the Norton anti-virus AND the Firewall.
Be sure you keep updating Norton, not just with the Live Update, which you may have set at automatic, but new virus definitions come almost daily, which you can and should download manually.
Just go to:
http://www.sarc.com/avcenter/download/pages/US-N95.html then just click on the ong.exe file, which has a date next to it, to identify the date it was posted, your computer will do the rest, You may have to click on "yes" to install it.
That should help some.
Zone alarm is going crazy tonight. 143 alerts in 45 minutes. Mostly to UDP port 41170. Why does this not match the one given throughout this thread?