ZoneAlarm Security is mainly designed to provide online PCs with protection from being attacked by any hacker or cracker. Its effectiveness and efficiency are obvious, coming from its four chain secuity services: firewall, application program, Internet lock and protection zone.  The newer version has additionally function of IM secuity and Web Filtering. All these secuity measurements inevitably make this software extremely difficult to uninstall. There are few things you should pay attention to in the Registry, when you are conducting uninstall to ZoneAlarm Secuity directly from Control Panel:

HKEY_CURRENT_USER\Software\Zone Labs
HKEY_CURRENT_USER\Software\Zone Labs\zonealarm
HKEY_CURRENT_USER\Software\Zone Labs\zonealarm\plugin
HKEY_CURRENT_USER\Software\Zone Labs\zonealarm\plugin\obj
HKEY_LOCAL_MACHINE\SOFTWARE\Zone Labs
HKEY_LOCAL_MACHINE\SOFTWARE\Zone Labs\TrueVector
HKEY_LOCAL_MACHINE\SOFTWARE\Zone Labs\ZoneAlarm

All the above entries should be deleted menually if you find them leftover after the removal.

Alternatively, performing the uninstall with Perfect Uninstaller is a more standard and easiler way to remove ZoneAlarm, by which can also take you away from the troubles of locating and deleting registry entries:

1) Getting into Safe Mode to totally close the service of ZoneAlarm Secuity.
2) Launch Perfect Uninstaller.
3) Highlight ZoneAlarm Secuity on the main panel.
4) Click “Uninstall” button and “Next” to begin the uninstall.
5) Follow the on-screen prompts to finish the removal.