2 Days ago the sound just stopped working on my 12" 1.5Ghz Powerbook. Has worked fine since the day I got it. No problems when upgrading to Leopard, it just quit out of the blue. When I use the volume keys on the keyboard, I see an icon that looks like the circle with the line through it. I check in sounds in the System Preferences and it states that there is not an output device. The system profiles shows the sound card. Any ideas anyone?