Barnes and Noble wants their users to be entirely dependent on their Nook hardware and their line of Nook apps for Android, iOS or Windows 8 to read your e-books.
Last September Barnes and Noble suspended the ability for users to download their purchased e-books to their computers from the Nook website. This ignited a firestorm of controversy, as thousands of users lamented they could no longer backup their digital editions.
Barnes and Noble has now gone a step further and redesigned their digital encryption. The old DRM system basically had your credit card data attached to the purchased book, in a safe and secure manor. Now it is being stored in a completely different way.
The only way remaining to backup your e-books purchased from Barnes and Noble is to use their Nook Study program. It is buggy and does not work very well, but it is the only option remaining to download your books locally.
Barnes and Noble really wants to lock down their customers into exclusively using their tablets, e-readers or apps. They want everyone to depend on the cloud to store purchased content and download it at a later date. If the bookseller were ever to go out of business, customers would be out of luck with anything they ever purchased, with no avenue to back it up and read on your PC.