Before even looking for a PC try just turning off the CF10 and then back on, the keypads should go through a stage of looking for master, master found, loading project and then to their normal menus. Takes from 3 to 8 minutes depending on the size of the program. Then if this doesn't fix it look for the pc and restart it. You do not need to actually login to the landmark software in order for the program to run, just leave it at the main login in window.

Look for a blinking red light on the back of the MCU, should beat like a heart beat, if it's off or solid that is a sign it needs to be reset.