If you attach a keyboard to the large round DIN on the right side of the unit, you can issue a Ctrl-Alt-Del command that will bring up the Task Manager. From the Task Manager you can End Task the election software to get you back to a desktop screen. From there you can perform a shutdown, using either the touch screen (START button) or using the keyboard (Alt-F4).
There is a cable you can reconnect to the smart card reader or ensure that cable is securely plugged in on both ends. Bot ends of that cable are accessible by removing the front blue panel. Be careful not to pull the blue panel too far forward when removing otherwise you could strain the connections.