Respuesta a "Does anyone know how to remove debris from under the laptop screen?"As far as I know you can only clean under the frame as the lcd is a Sealed unit. There's some screws covered with rubber seals on the frame just undo them and remove the frame. That reveals some screws for the lcd, remove them and then the lcd should come away. Jus be careful of the ribbon cable attaching the lcd to the laptop.
Respuesta a "It won't turn on?"More than likely water damage. But try resetting the SMC hold shift-control-option and then pressing the power button while plugged in. Then turn on as normal.
Respuesta a "My tablet wont power on"Have you tried reseting the device? Hold volume up and power button until you see the startup screen.