Well, hard to diagnose over the 'Net. Take it to a tech and see what they say would be my first option. If you did then call Customer Service. Just can't really help without having it in my hands.
Call Customer Service or take it to someone who has a proven track record. I'm going to close this because there is no way you're going to get any better advice than what's already been given, although you no doubt would get a bunch of scientific wild-ass guesses which would be worth exactly what you pay for them.