Hi Robert
Had same trouble with my JVC GR-D21EK . I took the camera apart to get to a white plug by the battery slot on the PCB . Unplugged it for a minute.Repluged and reassembled that does a Hard Reset back to the factory settings. There were 11 screws to remove of different lengths to make a note of. Not a job for the faint hearted.
Best of Luck
Harold Tokins, November 2010