So my buddys mac wouldnt boot. Replaced the HDD and have been through hell trying to get the OS loaded. I tried Internet recovery, and a bootable USB. Neither of which worked. Then, I borrowed my other friends mac to do a time machine backup, and try to restore the troubled mac with it. fail. Then I decided, why not pop in the HDD I know is working? Did that, and still, nothing. It sits at the apple logo with the spinning wheel and will not go anywhere. Does anyone know what the problem could be? Here is the link to the other thread I have open (i thought the hdd was the problem originally, until I put in a known working drive). http://forums.macrumors.com/showthread.php?t=1622203 Thanks for the help in advance guys!