An update for general info, again to be taken on board as required.
About six weeks ago, on top of the inability of the iMac to play music, it developed a dead pixel line almost exactly down the centre of the screen. If ever there had been any doubts about its unsaleability (?) they were removed.
Then, almost as though by spiritual intervention, the sound problem fixed itself and has remained fine ever since. Though the slightly irritating line down the centre of the monitor remains, it is rather like a mild ache in that you learn to live with it and eventually don't even notice it's there. So I continue to use the iMac as my desktop machine and appreciate it for the good things about it.
What bugs me though is the competence of the service agent. You have a car that you paid well above average money for, let's say a Honda. You bought it because so many people tell you how well it is put together. It does everything you need and more, because in truth your needs are simple and could basically be met by a baby Ford.
Out of the blue develops an engine noise which manifests itself in a narrow band just around the speed limit. It's not deafening, but it's irritating. The car still performs its normal duties admirably and without a hint of a problem. You take it to the only dealer in town and ask them to investigate. It's out of warranty but you figure it can't be a major problem. After they've had it for a week, they present you with a basic service charge and the advice that you will have to replace the engine. You tell them to shove it.
Six weeks later the noise disappears and doesn't come back. How do you feel about the competence of your dealer? Should I make a complaint to Apple Australia or would I, as I suspect, be wasting my time completely? What could it achieve?