Is your brand new Nook Touch lasting 4 days instead of 2 months? The Nook Touch can't hold a charge? This is the problem I ran into days after getting this wonderful new e-reader.
This appears to be a software problem. To "fix" the battery try the following.
(1) Turn your Nook all the way off. Hold the On/Off button for like 5 seconds. A popup will appear asking if you wish to turn off the device. Confirm this and let the machine go off. Wait a minute or so. Hold the On/Off button for about 5 seconds to get the device to turn on.
According to the Nook forums, this has solved the problem for a number for people. However I had to do a little more.
(2) Let your Nook battery run all the way down. The Nook will display a message stating that you must plug in your Nook if you wish to turn it on. I was unable (or too impatient) to drain the device any further. I then plugged the device in for 4.5 hours. Then I did step (1) above.
The 2nd set of steps was given to me by Nook tech support. It worked for me. If neither of these methods works for you, please call Barnes and Noble Tech Support.