If the Altiris Agent (Symantec Managent Agent) encounters an unexpected issue and becomes hung / non-responsive (e.g. HOWTO42388, HOWTO36013), you can use one of the suggested methods below to recover the agent process. Sometimes these methods are needed when attempting to apply an agent update that contains a fix for the issue being encountered, since the agent is unable to receive policy updates or install upgrades if it is hung.
If you have access to Deployment Server 6.9 and the Altiris Client is installed, you can send a job to restart the Altiris Agent service
You could use the RAAD tool and use the options available for services. (See HOWTO21449 "Remote Altiris Agent Diagnostics 2.0")
You could use Active Directory and send a login script that restart the Altiris Agent Service