XP SP3, fully up-to-date
ZA free firewall version: 9.2.106.000
TrueVector version: 9.2.106.000; Driver version: 9.2.035.000
Microsoft Security Essentials
ZA control center has been randomly freezing in last couple of weeks. Double-clicking the icon in the system tray does nothing; right-clicking the icon doesn't give a context menu; red/green traffic bars freeze too.
Firewall itself seems to be working even when the control center is frozen because ShieldsUp!! (grc.com) shows all ports are in "stealth" mode.
Even after ZA control center freezes, everything else works without any issues. Only fix for ZA is to reboot which usually brings up a box saying ZA won't shut down, but clicking "End Now" button causes a total freeze requiring a cold boot.
All malware scans are clean.