Hi all, I seem to be having a problem. Yesterday, a screen popped up saying that I have to restart my MBA by pressing the power button, which I did. However, since that time, I have had absolutely no sound whatsoever. When I use the keyboard to try to raise/lower the volume, I get a little circle with a line through it. This happens whether I have headphones in or not. Even at the top of the screen, where there is usually a volume control, there is just a space where it should be, next to my wireless interned indicator. I'm wondering if anyone else has had a similar problem and if so, how do I fix it? It's totally driving me crazy. Thanks!