Step 1)
Open up the services control panel (start, run, services.msc)
Find the agent service (ex: Quest Change Auditor Agent) and go to the service properties.
Set the service start up type to be disabled, click apply, click the stop button, then click "ok"
Open up windows explorer and navigate to the Change Auditor folder
Examples:
C:\Program Files\Quest\ChangeAuditor\
C:\Program Files\Quest Software\ChangeAuditor\
C:\Program Files\{other folder}\ChangeAuditor\
Delete any "Agent" folder(s)
Step 3)
Delete the following registry key folders if they exist
HKLM\Software\QuestSoftware\ChangeAuditor\Agent
HKLM\Software\Quest\ChangeAuditor\Agent
HKLM\Software\{other}\ChangeAuditor\Agent
HKEY_CLASSES_ROOT\Installer\UpgradeCodes\8C5121E10D9312B41B1B57FF03F74BD7
Step 4)
Open up a command prompt as administrator
sc.exe delete "service name"
(ex: sc delete "Quest Change Auditor Agent")
Please make sure that the name of the service you are trying to remove exactly matches the name in the sc delete string.
Step 5) (optional)
You will now have to go back into the registry to remove the latent "uninstall" entries in the add/remove programs menu.
Make an export of the following Key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall
Once that is complete, look in sub items within that key for any that contain the "Display name" key that has a value similar to:
ChangeAuditor Agent
Quest ChangeAuditor Agent
Step 6) (Possibly unnecessary, this will have to be tested)
You will likely need to reboot the host to make sure that anything that is in memory gets washed out and the registry changes get reloaded.