In our environment something corrupted our Win2k Machines resulting in them only checking in at boot. Diagnosing & troubleshooting has exceeded the value of the systems in question so we created a scheduled Task Server Task to restart the Altiris Agent on Win2k system that have not checked in for 2 days.
Because Task Server communicates with clients differently than NS and would still accept tasks, this allowed us to keep our Win2k systems up to date until they are finally swapped.
This will not work if the aexnsagent service has actually stopped. Only if the service is running but fails to check in on schedule.