To make the Touch-Screen Assistant software open automatically when the computer is rebooted, during installation check the box to Automatically load when the computer starts. This should circumvent the Windows automatic updates that restart the computer but leave the desktop visible without any ability for volunteers to login.
To activate that feature when it is already installed, just reinstall with the Touch-Screen Assistant CD over the existing application, allow the installation to locate the existing installation paths.
You can also check the box to add a shortcut icon to the desktop.
To stop the Touch-Screen Assistant from staring up automatically upon bootup, delete it from the Windows Startup menu. Conversely, to make the Touch-Screen Assistant automatically start after it has been installed, drag its shortcut to the Startup menu.