This afternoon I checked my watch and t was showing just over 12,000 steps. This evening I went for a run, but the GPS was switched off and could not be switched back on. The Activity button doesn't work. In fact none of the buttons apart from the power button work. I've powered it down, plugged it into the computer done a reset. Am I going to have to take it back to factory settings? If so, how do I do that?