Have you tried powering off the NC and then powering on? Press and hold the power button until the screen goes black. Then press and hold the power button for a few seconds until it reboots.
If that doesn't work try pressing and holding the power button and the physical N button below the screen for about 20 seconds.
What petesnook wrote should fix it.
Also try this on ONE BOOK to test.
1) Archive the Book.
2) Restart Nook.
If that fixes it for the book then let us know.
well, I got brave and did the N and power thing and it is fixed now. so I didn't try the archive solution. Does anyone know what caused this problem in the first place? just curious and I am using the nook for travel so I'm not always in a good position to ask for help. Thanks to Petesnook for the solution and to both of you for responding to me.
Glad that solved the problem without having to do a factory reset. Hopefully you won't encounter the anomaly again.
The power-N trick solves a lot of unexplainable problems. I think the Nooks have problems with memory management. In Windows I'd blame page handling, but I have no idea how Android does its memory management. Obviously power-N does more than just reset RAM since the normal power off would/should clear RAM. I'm just happy that it works as well as it does.