HELP PLEASE! I downloaded el capitan from apple, but when the installer finished downloading and starting installing, it displayed the black screen with apple logo and the bar below, and after the bar was full, it remained in this state forever, and it never get in osx. I have to push the power button, I open it again, same thing again. I am not having a working computer now! Why it stuck? Is there a solution? What can I do? I need my mbp working even with yosemite, but I cannot get in! Please help me, as I am stuck out of my machine!