Hello, I’m Nathan, and I’ll be assisting you today. My livelihood depends on your positive feedback, so your satisfaction is my highest priority.
Sorry to hear you’re having trouble.
This symptom can indicate several possible issues: an internal hardware failure, a low/faulty battery, or just a simple memory/firmware glitch.
The first step here will be to attempt to reboot the kindle. This is done by pressing/sliding and holding the power button for 20+ seconds, or until the screen flashes (usually with an image of a tree), then release. Note that you may need to repeat this process 4-5 times for it to take effect.
If the kindle still isn’t working properly, the next step will be a deeper level reset. If you have not charged the kindle recently or know that it is at least half full, then you should charge the battery for at least a few hours before proceeding further. Then plug the kindle into computer via usb cable, then press and hold power button for 60+ seconds, and release. The kindle will take 3-5 minutes to reload it's internal firmware. If it doesn't turn back on by itself, press power once to turn it on.
Let me know if the problem persists, and I'll advise further if needed.