I am using a Late 2009 Mac Mini. This afternoon I did a software update, it was 4 programs that were updated. I didn't take a look at what was updated, which was a mistake, I know. But anyways, they installed fine, and the Mac rebooted, it got to just before the user select/login screen and hanged there. I was able to move the mouse around, but nothing else, and after a long period of time, I powered off my Mac, and now it is hanging at the Apple logo. I tried booting into Safe Mode, and the grey progress bar would appear but and get half way through and then disappear. Next I tried inserting the Install DVD, hold down C while it was booting up but that wouldn't do anything. :/ I am out of ideas for what to try.