What list of things should I do to fix a stuck or unresponsive power button?

1. Check your power button – Check the power button itself is not stuck and fully functional.
2. Check the battery settings – Make sure your battery settings are set correctly within your device settings.
3. Re-start the device – Reboot or re-start the device to see if this fixes the problem.
4. Check the connection – Check the connection between the power button and the device motherboard.
5. Replace the power button – If all else fails, then you may need to replace the power button.