I got my NST at the 'Black Fri' sale 2 months ago.
I copy/paste news items of interest into my word processor
and save/print them to a PDF file, then SideLoad to my Nook.
After the Xmas holiday, I had other priorities and left it in a well padded
zipper organizer 'asleep' (not OFF)... well, the battery ran down.
I was unable to get it to take a charge at all...
There was enough juice left to let me know the battery was 0%
and then it would revert to the "your nook is starting up..." screen.
a few Googles suggested that I disconnect the battery as a "jolt"
to the system to let it then begin charging the drained battery...
I found this 5min video that shows how to remove the PWR-button
and a (tiny) Torx-5 screw to get the back cover off.
I would add that you should place a PermMarker-DOT on the
small power connector before you pull it out... so that you can
get it back in properly oriented... That was my one difficulty.
While the battery/back-panel was removed, I plugged-in my
usb-pwr cable to the nook... it glowed-Green (not reddish-amber)
but would not start up...
I replaced the battery and back panel...
plugged it back in and it began charging...
After a 3-4 hour charge, it was 100%...
Running again, seems OK.
I hope this helps.