I recently took my iMac 7,1 took the Genius Bar (running the newest version of Mountain Lion) because it was freezing (not entirely--everything frozen except for mouse cursor), and I was occasionally getting a garbled screen, which seemed tied to the freezing. After their tests and diagnoses, they told me they found some errors on the hard drive. The hard drive has been replaced and is not that old, though, so I wanted to read several forums online to see if others have had similar problems before I replaced the HD. One person on this site who had similar issues said it turned out to be the HD after they ran a SMART Utility. So I downloaded a SMART Utility program to run the test, and it did say that my HD has errors. My question is this: is there a way to figure out that the problem is the actual hardware (the HD), or that specific files are causing the errors/problems? Can files even cause these errors? If so, how do I find and isolate them? I'd hate for the issue to be files and not the HD, and replace the HD, put my files on the new HD, and then face the same problems because I just put problematic files on my new HD. I'm not terribly tech-savvy. Please help!!