Try pressing the reset button to the right of the micro usb port at the bottom. Hold it in for about 15 seconds. I had a screen that refused to wake up. The reset solved my problem. None of your books will be lost.
I don’t know the EY21 case, but in my experience with Kindle I have found that each model has a slightly different case, and that if any case is even a slight misfit it will not be useful on a different model. How about ringing Amazon Customer Service? They are kind and patient and have many answers.
Unfortunately you cannot do it this way, however if you highlighted a passage in a book on your Kindle, you can login to the Kindle Online Reader and any notes or highlights should display in there. You should then be able to copy this text from the browser and in to a word document.
I don't know the answer to that one either. I just buy the books I want to read - they are not expensive from Amazon. But if you want to read something really, really good, I recommend The Blue Roses of Orroroo. I know it is good because I wrote it. Yes, that is blatant self promotion!