A friends IMac was running really slowly. And no back up.
At first I tried to get his data off the hard drive but I was unable to do that. Then I ran Disk Warrior to repair the directory. Well over 30% corruption. I'm surprised that it even attempted to repair it. It seemed repaired and then I ran Disk Utility disk repair. Seemed good. Load the system disks then crash. Did this two times but no deal. Installed new hard drive all is well.
Back up Back up Back up. At least two places. My friend has lost his info but at least he has his IMac back. Sorry know photos. But it was easy. Make sure you get the proper sucker clamps to remove the glass screen.