Windows Explorer and ZoneAlarm

System – NT4SP6a. Recent upgrade of ZoneAlarmPro to 3.6. And now, at shutdown, a program fault, attempt to execute a 00000000 instruction, in Windows Explorer. If ZoneAlarm is closed before exit, no error. Now, this is not critical, just continue closing, but. Everything reinstalled including SP, no help. Now last try, reinstall Esplorer. Can I do that without a full new WIN-NT?