Hello, I just got an ibook from someone today and the sound does not work at all. I have already checked to see if anything is muted and I have also tried headphones. It is a M6411 special addition if that helps anything and it has OS X installed on it at the moment. Also it seems that the dvd drive will only read dvds and not cds. I'm not quite sure what that means either. any help anyone could provide would be most welcome.