I have same problem too. No sound, a red X by the loud speaker symbol and a message that says "No audio Output Device is Installed". I have tried all the usual things like uninstalling drivers, reinstalling the original driver and so on but nothing seems to work. I am using a Pavilion laptop running Vista.
Is this a sign that the sound chip has blown ? How would you test for this or can you ? Is this economically repairable or does it require a new motherboard which would be too expensive ?
Any advice welcome. Thanks.