If you kindle is not responding to your command and it is stuck then you could try to do a hard reset. It is recommend that before you carry out a hard reset that you have backup all your data. If anything goes wrong you could always restore your data. Once the devices has been resetted it will goes back to the default manufacturer setting. Here's how:
1. Slide the power button to the right.
2. Hold the button for 15 seconds or more.
3. Now release the power button.
4. Press and hold the Home button until you see the device start up.
5. If the devices is still unresponsive you could try to recharge the kindle so that it has full charge.
6. Continue this step if the device is still stuck, go to the password request section and enter resettofactorysettings all in lower case. Continue to do this for a few times until you see it works.
Use a pin or a paper clip and push the reset hole. Here's how:
1. Turn the kindle device facing down.
2. Take out the back cover.
3. Locate the reset hole and use a paper clip and push it down.
Note that depending on which version of the Kindle you are having, each solution will work for the different Kindle device.