The main issue with a black screen tends to be the battery. Take the battery out, hold down the power button for a full minute then restart the computer. This should do a hard reset and get the screen to work again.

The simplest answer would be that the keys are stuck. Hit the Esc key multiple times until a setup menu appears on the screen, the reset the keyboard function. If this does not work, the keyboard may be unresponsive due to overuse and need to be replaced.

The fan in the laptop could have dust built up on it. To fix this, take the fan out and clean it. You can do this by blowing air on and around the fan to clear off any dust. Another problem could be that the fan is blocked and needs a chance to cool down. Do a hard reset of the device, then lay the laptop in a cool area with the fan facing up so nothing is blocking air from it.