When installing the ITPAM Agent silently from a command prompt using the instructions in the documentation, the agent gets installed but the Windows Service does not.
Process Automation 4.x
While root cause was never found for this case, the workaround is to issue a second command to install the Window Service for the Agent.
Right click on the command prompt window, open it with "Run as administrator" and execute the following:
cd "<PAM Agent Installation Folder>/PAMAgent\wrapper_64\"
c2oagtsvcinst.bat 0