Without opening and viewing the boards, this is a tough one to answer. High pitched noise may be a servo motor that is unhappy, multiple components also make sad noises, just before they let the smoke out. If the board is unresponsive to the power switch, then something has gone wrong somewhere in the logic board. Be careful on the insides of these, as the batteries hold a bunch of energy, and we have all seen the videos of these types of boards having much flame come out when the pixies inside are angered.