There is another reset that is sometimes effective. Place the unit on a charger for a while to make sure that it has some battery charge. Now, remove the charger and hold the power button for 15 seconds. If you slip off the button, restart the interval. When the unit starts, place it back on the charger and fully charge.  You can play music during the charge.

Note that this is not a Factory Reset.

Thanks - I will try that out.

Thanks so much, Buzz. That has done the trick! Great info.