Hello, I have a 2012 model for the Macbook Air that suddenly crashed on me as I was working. It now appears with the question mark folder icon blinking when I open it. I held down "Option" and it started to do an internet recovery. Afterwards, it gave me an option to Reinstall Mac OS X. When I get to the step of Select the disk where you want to install Mac OS X", it is blank. What should I do?