Try below steps. Attach the charger so the device is charging. While charging: First try to hold the "Volume +" and "Phone" buttons at the same time for more than 3 seconds (this resets the Flip 3 to factory settings). If this does not help, press and hold the "Volume +" and "Link" buttons for more then 10 seconds (this will exit demo mode). As a last step, short press on the "Volume -" & "Volume +" & "Phone" buttons. If the device will still not turn on, it has a defect.