Hi, I'm Nathan.Sorry to hear that you're having trouble with this but I'll do my best to help you.
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. Give the kindle about a minute to start back up, and let me know if the problem persists, we can then try some further steps.
Based on age, it honestly is not likely to work, but we can try a few more options.
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.
No problem at all, let me know when you have a chance. I'll be watching as well, I have some friends competing in Rio this year.
Do you need more help with this?