I have serious issue with MacBook Pro. It has two OS - Mac OS X (Lion) and Windows 7 Ultimate. Yesterday Mac OS X was turned on for maybe 15 minutes, and suddenly it freezed. So I had to shut it down with button. Then I turned it on with pressing Alt to get to the choosing Windows OS or Mac OS X or Recovery HD. But there was no Mac OS X choice. It dissapeared. So I tried to turn on Windows. It freezed on "Starting Windows". Then it restarted itself and gave me choice to start windows normaly or with repair. So I started repair. After maybe hour of progressing, it wrote that it could not be fixed. I tried this same thing two times again and finally Windows could be started. But it was not working well. Everything what I tried to start was starting about 10 minutes, for example internet browser Opera. And when some program started, it was not responding. Also when I tried to get to the Mac files trough Computer - Mac OS X - Users, it started to not responding. Next thing I did was turning off computer and turning on with pressing alt, and choosing Recovery HD. There I tried to reinstall Lion, but I could not because every part of HDD was locked. I can not use "Restore from Time Machine backup". I tried First Aid in Utilities, to verify disk Mac OS X. It wrote: This disk needs to be repaired. So I clicked repair. It wrote error: Disk Utility can´t repair this disk. Back up as many of your files as possible, reformat the disk, and restore your backed-up files. So Windows is working but with freezing and not responding, and I can´t get to the Mac. What should I do? How to back up files and reformat the disk? Is HDD dead? Will I be able to get at least files from Mac?