Was the NOOKcolor plugged in while your girlfriend was using the keyboard? I've read many instances where having it plugged in intensified the sensitivity of the keyboard. Most have said the problem goes away when it's running on battery. However, others have reported that the problem was resolved when they gave the touchscreen a good cleaning. I'd try those and if that doesn't resolve your issue then I'd see if you're still within your exchange window.
Thank you. Yes, it was plugged in at the time. I will give it a good cleaning and give it a good testing with it running on battery.
Thanks again for the help.