Once you have hit the threshold for it to stop logging, then it will not strart logging again until you are in a new session...reboot.
If you have a router or a modem that does NAT, then the built in firewalls in those hardware pieces will block incoming intrusions. On the ZA forum, we find 9 out of 10 times the logging stops is because a user has changed or added hardware that is now blocking.
If you had a other than normal shutdown, then your database could have gotten corrupt requiring it to be purged and reset. A 'clean' install should have done that. If you would like them, here are instructions on resetting your ZA database. You will lose all your customizations in ZoneAlarm.
1. Go into the Overview Preferences tab and turn off "Load ZoneAlarm at startup".
2. Reboot into safe mode. {
Instructions if needed}
3. Go into the folder named internet logs {do a search if you don't know where it is in your OS}.
4. Delete everything in that folder.
5. Empty the recycle bin.
6. Reboot into normal windows.
7. Restart ZA manually.
8. Recheck the "Load ZoneAlarm at startup".