Hello rhutchison;
I would suggest first to power cycle the MPU and while it is off to unplug and plug back in the keyboard several time, then turn the MPU back on and wait for at least on full minute Test the keyboard for oepration, if it does not work, try another USB port on the MPU and test the keyboard for operation. Disconnect the currently being used keyboad and use another verfied to be working keyboard, and test the keyboard for operation. Next I would use the cable furnished with the MPU and connect to the MPU "SET UP" port on th rear panel fo the MPU this ill be a PUTTY serial conenction and it is a text only console, I would perform a factory default from there. If non of this works I would call (888)793-8763 and start a support case.
Regards;
Danny