If you are using Windows XP....don't waste your freaking time...just use the built in ICF, Otherwise get it. Software firewalls are crap anyways. Four minutes max and I could be inside just about every major software firewall available. If you are using a xDSL connection, your modem should have a firewall built into it...if not buy any Linksys router and now you have a formible hardware firewall..MUCH safer. Also it will not slow your system down by hogging resources. If you ABSOLUTELY have to have a softeware firewall and have NO other choice then grab ZoneAlarm. Do not screw with Norton. It has more flaws than a seventy year old has varicose veins.