Not conflicting my friend,
NIS firewall is configured to block known intrusions and threats, so it is not a full firewal.
It does not block applications accessing the internet.
So it is not extremely powerful, yet but reasonably good.
Besides NIS safe web toolbar is very good. Works in IE and FF. So i wont degrade to NAV
NIS smart firewall failed the leaktest, it automatically allowed the leaktest app to connect.
Thats why i use Comodo as a full firewall.
Comodo asks my permission whenever an application tries to access the internet.
BTW, I use Norton AV and Outpost Pro in my other PC.