Are you having a problem with Apple's OS X 10.7 Lion during installation?  Has your install of Lion failed or caused your Mac to crash?
If you have recently tried to install Mac OS X 10.7 Lion and it fails, you can restore your TimeMachine backup of Snow Leopard and retry the Lion upgrade.
If you don’t have a backup, we recommend using  Data Rescue 3 to scan and recover your files BEFORE attempting to reinstall Lion again.   Data Rescue 3 will copy those files over to a 2nd hard drive as a safety measure, before you try to redo the Lion install. Simply reinstalling Mac OS X 10.7 Lion can possibly overwrite your files permanently, which is why you need to take the precaution of having those files backed up (copied over) to a 2nd drive.
Find out more about our mac recovery software here: