Well, after doing the hard reset as suggested above, erase and deregistering, and then re-registering, the NC seemed better. Not right, but acting up less often and severely for a couple days, then back to it's old tricks. Now it doesn't work when it's plugged in either, crazy.
So I called B&N customer support this morning and they've okayed a replacement that I can pick up from the Round Rock B&N store this afternoon. Yay!
Very helpful and a quick resolution to the problem.
I have three Nook devices. My NC, my NE1 and my NST. I've had to replace my NE1 once, an NC charger and now my NC. I've also called about problems with my account or the website.
CS has always been polite, helpful and worked with me to resolve my problems. When the website kept telling me that my cc had expired 50 years ago, they investigated and finally told me it was a reporting glitch and to ignore it. My account info was accurate and it would not affect my purchases or use of my NC. Sure enough, a few days later, the notice disappeared.
I very much appreciate that I've never had to argue with them about whether they needed to replace my devices and charger or not. This time, I knew my NC was over a year old and I wasn't sure it was still covered under warranty or not. I have it covered under Square Trade too so I wasn't overly worried about whether B&N would replace it or not, I knew Square Trade would cover it. But..they told me it was covered and set up the replacement for me to take care of today. Hopefully things will go as smoothly at the store though the store personel have always been helpful in the past.
Than you everyone for your help. It certainly smoothed the way this morning that I had already done all the recovery procedures suggested here, prior to calling so that we could move on to getting it replaced. That made resolving the problem a whole lot faster and less painful. 
And of course, I tried to be polite and patient in return and I think that ALWAYS helps when dealing with CS. OF course, that could change if the exchange doesn't go well. LOL! Thanks all!
well that was just too easy. I got my new refurbished nook color (well I got over a years good out of the other one so refurbished is just fine with me.) Hopefully I can go another year at least on the new one. Then I can get the newest nook at THAT time!! LOL!
Easy as walking in with my email print out, my nc and my charger, it was sitting there waiting for me. Yeah!
oh drats...now I have to set up my shelves and stuff again. Sure wish this could be done online to synce with across devices. 
Again, thank you all for your help!!
