I just bought a book but can't open it. - Tablets & eReaders

open account and see if card is up to date

Connect your previous Kindle to computer via USB, and you will find a new hard drive in "My Computer". Open the drive, use windows search function to find your files, next copy them into your computer. ... If your books are not bought from amazon, you can sync your kindle booksfrom kindle to another one easily.

How can I transfer books from one Kindle to another Kindle? - Quora

https://www.quora.com/How-can-I-transfer-books-from-one-Kindle-to-another-Kindle Can transfer my books from one kindle to another Google Search

you need to sort this out with your supplier or who you bought the books through
nothing fixya can do for you here

Check if the downloaded file is corrupted or if you are using the correct e-book reader.

This is nothing new with the reader. There are many problems, but check the following site to find an issue similar to others have found:
http://goodereader.com/blog/electronic-readers/the-kobo-e-reader-is-having-lots-of-problems

If it is a Barnes and Noble App that you are using, contact B&N tech support. Contact Customer Service

talk to customer service for KOBO. You may have bought a book in the wrong format for you reader. Also contact the place you bought the book from for a refund.