Never had a problem with NAV 2003 and older. AVG on the other hand has caused me BSODs and Avast! likes to block access to my router config. They all have problems.
It's the same with firewalls... only one firewall has never caused me any probs... Windows Firewall... but that's probably because it doesn't really do anything.
It's the same with firewalls... only one firewall has never caused me any probs... Windows Firewall... but that's probably because it doesn't really do anything.