Well, if you don't have backups - which you should - about the best you can do is check Office's Temp folder:
C:\Users\%Username%\AppData\Temp\
and check whether Word, Excel, etc. will open any of the temporary files there. Beyond that, you might have some success with file recovery software, but the prospects for success diminish with every time you do something that changes a file already on disk or add new ones to it.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]