Troubleshooting the Installation of the System Center Operations Manager 2007 Agent

Please refer the below link to troubleshoot the Agent issues.
http://blogs.technet.com/b/operationsmgr/archive/2011/09/01/troubleshooting-the-installation-of-the-system-center-operations-manager-2007-agent.aspx
For the most current version of this article please see the following:
2566152: Troubleshooting the Installation of the System Center Operations Manager 2007 Agent