Both XP desktop and Vista laptop had NIS 2009 installed. Desltop version was an upgrade from NIS 2008. At this point access from laptop to desktop shared folders and printers stopped (other direction was OK).
Re-installing NIS 2009 on laptop did not help (done by Norton technical remotely).
Re-installing NIS 2009 on desktop appeared to clear the problem, until a re-boot when it came back.
Installing NAV 2009 gave the same problem (after re-booting), i.e. it lies with NAV and not the firewall.
Installing NIS 2008 fixed the problem.
Am I better off with NIS 2008 on desktop and NIS 2009 on laptop?
Or is there a fix - I read that auto-protect (presumably on the network drives) is causing the problem - when it exists, I cannot even look at desktop shared drives with Windows Explorer (going through the network) from the desktop!