Strange one! Updated v3.51 to v4 - no problem. Both comps running XP Pro SP2 with ZA Pro firewall. After restarted comps, the 'network' bit in Zones disappeared and ZA was using 50% cpu trying to run. Couldn't get into za at all, just froze my comp when trying to access settings. Used the ZA /clean uninstall, reinstalled f/w and it went ok. No idea why but thought I'd mention it in case anyone else finds this problem.