I tried to install Snow Leopard. I got the error, "The contents of this disk can't be changed. Mac OS X couldn't be installed on this disk." I restarted, to boot from the startup disk, not the CD. And now it just goes to the grey screen and shuts off. Pressing "C" or "Opt - Command - P - R" or holding down the Power button for a while and then restarting, or trying "Command - V"..... none of it works. The machine just goes to the grey screen, the wheel spins, and it turns off. Thoughts? Did Snow Leopard just fry my hard drive????? If so, I'm P.O.'d!!!!