I posted this subject in the software forum, but have since discovered (by phoning Apple) that it now appears to be a hardware problem. This was my original post: I phoned Applecare who were very helpful and took me through a number of test to see what's wrong with the speakers. After 1 1/2 hours we tried the most obvious thing - plug some external speakers into the unit and see if they work. They did. So it now appears to be a hardware problem - most probably a loose connection (given that sometimes music plays, others it doesn't). SO, my question is, how easy is it to get to the wires to check if there is a loose connection? I could and should send my computer away to Apple but I really do need it. They say that it'll take between 7-10 working days to get it back to me, and for a loose connection this seems a bit of a waste. If anybody can offer any advice as to how to sort this out then I would be very grateful! Thanks!