Well, there could be something off with the buttons, I suppose.TWD Glasgow said:
I'd try a restart...from the home page, press the Menu button, select Settings, press the Menu button again, select Restart. It'll take a few seconds, and then the screen will go blank and the tree screen will appear. Let it do its thing until your home page re-appears
You might also contact Kindle CS; depending on how far over a year it's been, they might be willing to send you a refurbished unit or at least a discount on one.
(Amazon US customers inside the US: 1-866-321-8851, outside the US: 1-206-266-0927. Other customers, see here. )
Betsy