Yesterday, I started dowloading Apple's new software, El Capitan. However, once it asked me to restart to redownload, thing went wrong. After starting up, the dowload bar stayed at only a tiny blue sliver, claiming that the dowload would only need 23-24 more minutes. After waiting around 30 mins-1 hour, the dowload stopped, telling me an error occured, and asked me to restart, leading back to the same problem. I also could not boot up safe mode because my mac also has a problem where a grey loading bar appears at launch, and turns off the computer after loading. This thread was on apple support: https://discussions.apple.com/thread/5976669. Currently, I also can not acess the old OSX Mavericks through recovery, since the disk is locked. Now my mac is useless, and I can only use recovery mode's safari browser. Any ideas? Thanks in advance.