Intermittent Tartarus Pro Keyboard Failure

My Tartarus Pro had been working fine but now has frequent, intermittent failure of the keyboard. No characters are generated by the keypad but characters are generated by button 20 and the joystick. Things that fix the problem include: rebooting. Things that do not help: connecting "directly" to the computer, changing profiles, making a new profile, unplugging and plugging in the device, removing and reinstalling the PC software. This is incredibly annoying, please advise.