Barnes and Noble has likely introduced a new hardware revision which bricks your unit if you install their official 1.0.0 Firmware (A step needed to root). As of right now, Nooks with serial #s starting with 1003 (running firmware 1.4.1) cannot be rooted, and should NOT be attempted. See New_Hardware_Revision for more details

From nookDevs

Choosing default launcher

Using VNC

1. Run WiFi Locker to lock the wi-fi on and disable screensaver
2. Press the nook Home key to enter the launcher selection screen
3. Run VNC on a computer with adb
4. In VNC, click the checkmark for default and then run a launcher to make it the default