Trying the Control + R during startup to get to the screen with choices for recovery or reinstall. Let it run all last night and never did the reinstall. Just kicked it off a minute ago and fingers crossed again. Took it by a shop last night and they ran diagnostics that indicated both HD and memory were OK. Since it has not worked yet, can anyone tell me exactly what to expect after the "Downloading additional components. your computer will restart automatically." completes. I was asleep by the time it would've run last night, so never saw if it actually restarted. When I awoke it this morning it was back at the screen with the choices for recovery or reinstall. OK, it got down to less than 20 minutes remaining, then jumped to over 5 hours, then jumped to the Mac OS Utilities menu with choices to Restore, Reinstall, Get help or Disk utility. Why is it not reinstalling Mac OS X? Any help?