2009 27" IMac won't boot. And my time capsule appears to be corrupt. I have saved my iPhoto info to an external HD, but thought that time capsule had me covered from the rest. When I try to repair the HD from disk utility, it says it can't be repaired. How can I save data before I reformat? I've seen posts about booting Lion to an external HD, but can I still save data is the internal HD is unrepairable?