Failed nook number two

I'll be calling Barnes and Noble soon. My first nook needed replacement. In a sign that they either have a huge quality control problem or I'm a victim of bad luck, my second nook seems to need replacement as well. Yesterday, I plugged my nook into a computer and let Calibre sync a few news feeds. When I checked back hours later, it complained that it had lost connection to the nook. Windows itself was unable to see the nook's contents, although it did appear to be mounted. I noticed the amber light was on which after that many hours should have been green by then, indicating the battery was full.

The nook is stuck at the USB connected screen. I've tried everything to no avail:

• Unplug and replug.
• Remove the battery for a minute and reseat it.
• Try to power the nook with the battery removed.
• Remove the battery for an hour.
• Hold the power button for 10 seconds... 15 seconds... 30 seconds... one minute... 
• Hold the left previous page button and right next page button simultaneously (forum tip which I didn't expect to work).
• Hold all four page turn buttons simultaneously (another tip I didn't expect to work).
• Mutter under my breath including a few words that can't be repeated here.

In all cases, I was unable to get the nook to reboot, nor get the charging light on. About ready to admit failure, I plugged the nook in and let it sit overnight. No joy!

I'm obviously fairly certain it's not an issue with the charger. I tried three different Micro USB cables, including the nook's own cable, the Kindle's cable and a generic one I had purchased off of MonoPrice. I also tried connecting via two computers, two different outlets, and via the nook's AC adapter as well as an adapter that came with an iPhone, plus the Kindle's AC adapter. 

I'm fairly sure it's safe to say I tried everything an end user might be expected to try. I'll report back on my experience calling Barnes and Noble tomorrow, since I just don't feel like calling them now.