Hello Everyone, I have a 2009 imac that started freezing up more and more a few months ago. I reinstalled the OS Yosemite, and the system worked great for a few weeks and then it started freezing up again. I reinstalled the OS again, it worked better (but not great) and when I woke up this morning, the imac has the folder with a question mark blinking. Could anyone help me with this issue? Is it my hard drive?