Personally, i'd take the whole thing to bits and put it together again and plug it in (works for cars[maybe without the plug it in bit but you get my point]) Add a new battery first (again works for cars and iPods often) then your iPod should tell you what its problem is by its error code, or maybe its just old and fed up with its software and wants the funky new (3.1 lol) software update, works for me a lot of the time.