BlackIce Defender is possibly the
WORST firewall program ever written (yes, even worse than Win XP's built-in ICF)!
I would
STRONGLY recommend getting ZoneAlarm from
ZoneLabs and using that instead.
As for Norton AntiVirus, make sure you have real-time protection enabled and Norton SystemDoctor disabled. You'll also want to allow Norton to run LiveUpdate every time it says to (defaults to every two weeks). I've used Norton for four years across about a half dozen computers (all using always-on, broadband internet connections and running anywhere from Windows 98 to Windows XP (minus Windows NT 4) and even worked with their Corporate version some. And I've never had a problem with virus infections.
From my experience with that program, I'd be inclined to say that the reason you are having problems is because it's a bad install or you configured it incorrectly.
I have also worked with AVG from
GriSoft and, even though it is free, it also works very well. In fact, it's what we use here at work and what we recommend to others! If you really are having these kind of problems with Norton, I'd say go ahead and give AVG a try.