Dead HD ?
I have a late 2007 20" iMac running the latest version of Mountain Lion. I am now unable to boot into the OS. All I get is the flashing folder icon with a ? on top of it. I am able to boot into a backup of my Macbook which resides on a portable USB drive but when I go to the System Preference I cannot find my iMac's drive on the Startup Disk option. The only options are the Macbook backup and Network disk (which I do not have). Does this mean that my HD is gone?