try taking the battery out fo 30 minutes and disconnect the charger (but leave the charger pluggedinto the wall). Meanwhile press and hold the power button for 1 minute.
Next press and hold the Fn key and the Esc key down while you plug the charger in. Keep holding those two keys down and with your other hand press and release only the power button.
Keep holding "fn" and "esc" until it starts beeping and then you can let go.
In about a minute or two it should reboot.