missing nook

i upgraded digital editions to 3.0 I plugged in my nook and opened digital editions. my nook showed up, and there was a tab to authorize my device. when i clicked on it my nook dissapeared from the screen. I disconnected the nook and  stopped digital editions. reconnected the nook and restarted D.E. . No nook

looking in, my computer tab in windows it only shows my nook as a removable drive. i cannot open the nook and it shows it as a removable drive with no disk.

Help!