Unfortunatly i have to agree with Acuos! The files are wasted! Usually happens with larger scenes. Ive had 2 scenes, both about 700 mb, ruined in the same way. But its strange that your backups are corrupted as well! Perhaps an object in your scene, thats causing it. Or if your machine have been working for several days without being shut down, strange things can happen...

Rudolf Herczog
Digital Artist
www.rochr.com