My wife's Vivomove Sport has stopped working altogether. The watch hands do not move, and the touchscreen has stopped working, but there is a single white dot just above the 6. Connecting it to the computer, Garmin Express does not recognize any device. I have left it charging overnight. I've tried using different chargers and different outlets and computers to get it to wake up. Again I left it charging for over six hours this morning. Nothing seems to work. This is a relatively new watch, and is taken care of rather well. It's not around water, never in the shower or pool, not used during any strenuous activity. What can I do to wake it up?