I was having issues with my Mid 2011 iMac getting very slow when doing anything including backing up files to an external drive. Eventually it completely froze and I had to force shut it down. When it rebooted it it booted to OS X Utilities mode and I am now stuck. When I try to restore from Time Machine it doesn't see a backup drive even though I have verified on another computer the back ups are still there. When I try to reinstall OS X the only drive that I can choose to restore to is "Recovery HD" which is locked, my Macintosh HD is not listed as an option (I have since removed all external drives to preserve backups). Disk Utility sees my internal Macintosh HD but it is now showing with a different name it will not allow me to erase the drive. Not sure if pictures of the messages will help but I have attached them. I have a feeling my hard drive died but looking for any tips or things to try prior to taking it to an Apple Store.