Hello! My name is***** am a computer professional with over 15 years of experience with both Mac and Windows computers, phones, tablets, and printers. This problem and many others are often the result of a "glitch" in the software. Luckily, it is easily fixed.
Please do the following:
Remove the charger from the Kindle (it it's connected)and hold the power button or switch in the OFF position for about 20 seconds.
Release the button or switch, then connect the charger and try to turn on the Kindle.
If this doesn't work, please repeat the steps and this time hold the power button or switch in the off position for a full 40 seconds. This should reset the Kindle to factory defaults. You will know that it successfully reset to factory defaults, if it reset the Kindle back to the way it was when you took it out of the box. Did it do that? If not, please try it again, being sure to hold the power button for a FULL 40 seconds. If it did require you to set it up again, then the factory reset was successful.
If you do have to reset it to factory defaults, you don't have to be concerned about losing anything that you've purchased from Amazon. As long as you set the Kindle back up using the same Amazon account info you will be able to download all of your previous purchases.
If the factory reset was not successful (it didn't require you to set it up again, since your Kindle is a Fire(if it's at least 2nd generation), you should be able to a factory reset from here - www.amazon.com/myk. Go to My Account > Manage you content and Devices and click on the device tab. If it is available, you'll see REMOTE FACTORY RESET as an option in the drop down menu under DEVICE ACTIONS. Please note: The Fire’s battery needs to be charged to at least 30% and it must be connected to a Wi-Fi network. If this doesn't work, or of the option is not available for your Kindle, please let me know.
Please give this a try and let me know how it works for you. If this solves the problem., would you mind taking a moment to rate my service? I'd really appreciate it! Without a rating I am not credited for my answer. If you need more help, please tell me exact model of your Kindle. If you're not sure, please look for a serial number. If you can't find it on the Kindle, you can find it on the Manage Your Kindle page of your Amazon account (in the Manage Your Devices section).