Wierd - I replied this morning, had it confirmed, but somehow it disappeared.
In any case:
The Default Admin Password has been changed for the Router, so everything is set right there.
Does anybody know what specific NAV2009 options need to be disabled to make it compatible with ZoneAlarmFree?
If this is easily doable, then that would be my first choice.
In the absence of an easy fix there, my choices would be continuing as is, with possibly sub-optimal outbound protection, or considering upgrading to, e.g., Norton Security Suite, with its firewall.