We just get a new mac air. We were trying netflix video, and the browser did not response. Now It get a black screen and can't start. I tried to press power button, etc, but nothing works. We are rather new to Mac world. What are the things I could try? BTW, the Mac air comes with a power supply only. There is no DVD drive or thing like that. How do I re-install OS if I need to? Any suggested extra items are good to have? Thanks!