Many issues with your Kindle, such as a frozen screen or issues with downloading content, can be solved by restarting your device.
1. Press and hold the Power button for a full 40 seconds. After the first 6 to 8 seconds, the screen will go blank, which is normal. Continue holding the Power button.
2. After the 40 seconds, release the Power button. The charge indicator light will turn on after a few seconds.