So... my macbook won't start! I turn it on, and a page that says "you need to restart your computer" comes up. I have tried MANY things that were suggested to me. I reset my PRAM, which I initially thought helped, because the next time I ran the repair option under Disk Utility it worked (where previously it had not, and said "Invalid Sibling Link"). However, even after the repair "worked," I still could not boot my computer. It won't start in safe mode, and whenever I try to enter single-user mode, it freezes. I ran a hardware test, which said everything was fine, and as I said before, my Disk Utility repair said that everything was fine as well. So I'm not sure why my computer still won't start! Help! Under disk utility it says that my HD is not mounted... what exactly does that mean? And forgive me if I don't know much about this, I'm still pretty new to the Mac world!