A Kindle Fire screen can go blank when it locks up and becomes stuck on the gray or black screen. The Kindle Fire is still on, but it is not working properly.
Another reason why a Kindle Fire has a blank screen could be due to its battery dying. Fix it by plugging in the charger and wait around 15 minutes so it has enough power to turn back on. If this does not work, it is also possible that the charger has died. To fix this, purchase a new charger.
It is somewhat common for a Kindle Fire to lock up, be unable to charge and not work the way it is supposed to. The simplest solution to this problem is to reset the Kindle Fire. Resetting the Kindle Fire is a very easy process that takes about 20 seconds. Hold down the main power button and then press it again. The Kindle Fire should power back up after this.
There are many ways to save battery life and prolong the life of the Kindle Fire. Turn down the screen brightness, and turn off Bluetooth. It also helps to put the Kindle Fire to sleep when it is not in use.