autosave revised files

[Terrisanna]

I used to be able to automatically save a back up of an old file after revising when I saved the new version of the file. The timed back up doesn't work for me. How can I set up Microsoft Office 2007 to back up version 1 when I save version 2 of a document. I don't know how many times I've had to go back to look something up after it was cut in version 2. Any suggestions