macbook air won't function My Macbook air has OS X Yosemite 10.10.2 on it. There was a software update notification for it so I proceeded with the upgrade. After installation the computer restarted and during restart it went blank and displayed a black screen with a symbol. Every time I restart now that is what I get. Please see attached picture to see the symbol. How do I recover from this?

thank you,
Shar
I hope you have made a Backup of your Files. When it restart press cmd+R and install again the Mac OS X, after that you restore your files with the Backup.