Recovery
Today I installed a recommended OS update on my MacBook Air. When I tried to turn it back on, it was unresponsive. I tried pressing Command+Shift+Option+Start, and it eventually came on, but it was flashing a gray file with a question mark. I proceeded to take it to recovery mode by pressing Command+R, but was unable to fully recover my Mac. I could not recover the disk or reinstall OS X. Is there anything else I can do, or do I have to take it to a technician?
MacBook Air