Problem : I returned home after 3 weeks holiday. I turned on my computer which alerted me to various updates. I proceeded with the updates, and afterwards I found I was no longer able to play sound through my computer. I had jet lag, I was up late, and there was no-one around to assist me.
Solution : On my holiday to England, I read through dozens of backdated copies of ComputerActive a UK Computer magazine. I visited their forum :-
http://forums.computeractive.co.uk/index.jspa and posted my problem. Within a few hours I had several helpful responses, and was able to turn my sound back on. I suspect the updates turned it off. This forum is an invaluable asset for small business owners in Australia, especially as your technical problems are answered overnight.
You can see the thread here :-
http://forums.computeractive.co.uk/message.jspa?messageID=840346