Barnes and Noble has just removed the ability to download eBooks that you have bought from the online Nook Store. They did this so users could not download purchased content locally on their PC and either strip it of the encryption or use a 3rd party reading app.
The Barnes and Noble customer care division has sent out a tweet, letting people know that this is their new policy and not a bug. “The ability to sideload NOOK purchased content has been discontinued. We apologize for any inconvenience this may cause.”
If you own a Nook e-reader or tablet, you will continue to enjoy purchasing and reading books right on your device. Ditto for people who use the official Nook app for Windows, Android or iOS. This issue mainly affects people who use an internet web-browser and accesses their Nook Library. In the past, a download option would appear, but now this has been removed.
Read the full article @ GoodeReader.