Answer to "Is it possible to replace an Apple Watch Series 2 Screen?"here is the link for you https://www.youtube.com/watch?v=yAE3Q5ad...
Answer to "Why won't my Lenovo A7-40 power on?"If you can feel the motor is buzzing, try to check the lcd cable, many lcd cable faulty in this device, that`s my experience, or try to disconnect and put it back. If it`s not charging can be charging port issue or battery even motherboard. try to factory reset with the power button and the volume up button.