On an Amazon Kindle Fire it is a touch screen so you use your finger on the screen push up and the page scrolls up. Conversely to return to the beginning you point it down. You can eve enlarge the size of email or web pages by using 2 fingers pushing away from each other and it enlarges the print.
As for the screen, not a lot you can do about that. It is time for a new one. Your books if they are from Amazon will still be on your Amazon account those that are not transfer them to your PC or someone's PC for when you get your new Kindle. You should have them backed up somewhere anyway in case your Kindle is stolen or lost.
Hi Eva, the only help I can give you is probably the same as you have already been told but anyway. I have had times when my kindle also freezes and the only thing that works for me is to slide the sleep button over and hold it for the count of 30. You will get a white screen but leave it, it will slowly upload everything you have saved. It is like rebooting a computer and seems to refresh everything. It may take 5 minutes or so to finish depending on how much you have saved on your kindle. I hope this works. Robyn