Why block complete range of IP addresses....

Normally such IP blocking are undertaken at Network firewall level.. Personal Firewalls unless very critical should not set such rules.....

U can instead block the IP's of the unwanted connections.. It is simple when using IP tables in Linux...

I am sure such graphical utlity would be available with Norton. Also have u tried XP in built internet firewall....

It is worth a try....

Regards

Kalp