Yet ANOTHER Boot Loop Conundrum

Sounds like you have two roms.

One on the sdcard, which will only run if the card is plugged in (although there's a menu to also boot into the stock rom).

And the stock rom, which will be the only one that runs with the sdcard removed OR a blank card is inserted.

I thought you fixed the stock rom by flashing back to stock. What did you do to break it?

When you removed the bootable card, were you running the stock B&N rom or did you end up replacing it with CM7? (I couldn't tell from any of your posts.)

If it loops, there's a few things you can try...

For stock B&N rom:
1. (if rooted) Press "n" at startup and boot into emmc recovery.
(if not rooted), boot off a bootable sdcard first.

2. format cache, delete Dalvik cache and fix permissions. Since you're not formatting data (aka factory reset), you do not lose apps or settings, but the first boot takes several minutes longer.
3. do step 1,2 and reflash the stock rom. (It might be difficult to find the stock rom as a complete rom)
4. wipe everything in step 1,2 and format data (aka factory reset) and flash "back to stock" rom. This means you lose all your settings. Apps purchased in B&N Store will still be available.

For custom rom on your NC (emmc), like CM7, CM9, CM10, etc.:
1. Use a bootable sdcard and boot into emmc recovery and format cache, delete Dalvik cache and fix permissions. Since you're not formatting data (aka factory reset), you do not lose apps or settings, but the first boot takes several minutes longer.
2. do step 1 and reflash the rom (CM7, etc).
3. wipe everything including data (aka factory reset) and flash your rom. This means you lose all your settings. Apps purchased in Play Store will still be available.

For custom rom installed on sdcard (sdcard):
1. Press "n" at startup to boot into sdcard recovery and format cache, delete Dalvik cache and fix permissions. Since you're not formatting data (aka factory reset), you do not lose apps or settings, but the first boot takes several minutes longer. (Not easily done when your rom is on the sdcard, since it doesn't usually have a full version of recovery.)
2. do step 1 and reflash the rom. (It might be difficult to find the stock rom as a complete rom, but easy for a custom rom like CM7.)
3. format the sdcard and start over. This means you lose all your settings. Apps purchased in Play Store will still be available.