I have a 2nd gen. 32G touch. Bought it used (not smart). It randomly shuts down and has to be reset. After too many resets, non-apple factory installed apps don't work(original ones do). Seems to work fine if plugged in to charge. If unplugged, shuts down after it goes to sleep and has to be reset. I can't ID problem clearly. Have done a complete reinstall through itunes. Any suggestions?