This is a common issue, getting your computer to recognize your NC in adb. Some have an easy time, for others, it's a struggle. Here are the best tips we have to get it going. Let us know how it works out:
first, reboot your Nook and your computer and see if it changes.
If that fails, download and unzip this file, open install.exe, and follow the on-screen prompts (this will install drivers so your computer will recognize the nook).
If that doesn't work, try opening the Super User app on your nook and then issuing the commands.
If that still doesn't work, refer to the steps in this wiki, repeating if necessary.
first, reboot your Nook and your computer and see if it changes.
If that fails, download and unzip this file, open install.exe, and follow the on-screen prompts (this will install drivers so your computer will recognize the nook).
If that doesn't work, try opening the Super User app on your nook and then issuing the commands.
If that still doesn't work, refer to the steps in this wiki, repeating if necessary.