You can delete only an unmanaged computer, you cannot delete an agent-managed or agentless-managed computer. Before deleting an unmanaged computer, you must uninstall the MOM Agent. When you delete a computer, you delete all of the data associated with that computer, such as performance data, events, alerts, attributes, and service discovery data. Remember to delete any computer discovery rules that match the computer you are deleting; otherwise MOM will discover it again.
To delete an unmanaged computer