I have got to know about the problem in Norton's softwares that it is again asking for the activation key even after it is working for months. After seeing so many emails i had came to the conclusion that the servers at symantec are now checking the serial key each time you update your virus definitions. Therefore we advise you that you try to avoid the Live Update function if you want your Norton Internet Security 2006 or norton antivirus 2006 to be working as before, otherwise it will became crippled too.
If your copy of NIS is asking for the activation key again, then plz reformat your system, install Norton Internet Security or norton antivirus 2006 and update the virus database using intelligent updater only. Do Not ever use Live Update. Or else use the combination of Avast Antivirus + Zone Alarm Firewall. I am also using it for over six months and no virus or worm entered my system till date. Now it's ur choice
...from this links you can update your norton without control
http://securityresponse.symantec.com....download.html