just recently purchsed a nook color. i have bought several books, but one of them keeps asking for a unlock code. i put my card and name in but it still wont unlock. please help
Where did you purchase it? The unlock code should be your email address (your user name here on B&N) and credit card number with no spaces in it.
However, if you properly registered your NC, the books should unlock automatically. Since you say all but this one do....the one thing to try is to turn on the WiFi on your NC. Then archive the book and sync your NC. Then after a few minutes, unarchive it and download it again. It's possible the original download was corrupt and this would (should) take care of that problem.