I'm running 6 NXT robots in an introductory class.
Occasionally we've had bricks that would not accept a program and I've reset the brick by pushing the reset button under the battery pack as well as pushing the button under the USB port, experiencing the blank screen and "click..."
Re installing the firmware usually gets them going again. I have one brick that when cleared and reset will accept a download, but when the program is run, port B drives the motor at full speed, and nothing else happens.
I have reset the brick many times, and the problem still exists. I sent a query to LEGO and got a computer generated response that there would be contact in 1-2 days.... nothing after a week, Sent the same query again and got tho same auto response.... still no real contact (after 4 days)
I'm looking for suggestions.