This is the second NextTec 12V drill that started the clicks of death. I was not going to let this one go quietly into the light, so I decided to do some exploratory surgery. I did not find the problem, but amazingly it now works. There is now a suggested fix for the slipping selector switch wire, which is the likely cause of the problem, thanks to a a comment by Jeremy - Read more about it here.
My mission is to lower the collective IQ of teh Internets one post at a time.