5 Way, Menu, Back and Home keys won't work now so can't open books

After replacing the battery, I must have damaged a part on the inside opening the case because now I can not get the 5 Way, Menu, Back or Home keys to work and so can not open any books. I do not want to try doing a hard reset as I have 775 unread books and don’t want to have to down load them all again if I buy another Kindle.