Consider it lost if you didn't enable autosave. http://support.microsoft.com/kb/213943 tells it existed in the 1998 Macintosh version, and I can't imagine they left it out by now. But I can't check, because I only have the Windows versions 2003 and 2010.
Kees
I have an iMac running OS X 10.6.7. I was working a new exel document when power was lost to the computer. When it came back on the document was gone. I have been unable to find the document in Finder. Does this system automatically save documents in this situation, or should I consider it lost.

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