Are you saying that you have found a way to configure Excel to automatically
create backup files for all edited files? If so, how have you accomplished
this, and in what version of Excel?
Excel is documented to create backups for a specific file if you
specifically ask Excel to do it
http://support.microsoft.com/kb/141451
also Help for "Save a backup copy of a workbook"
but my experience with this feature in Excel 2000 and Excel 2003 is that it
only applies to the specific workbook that you requested creation of backups
for.
Jerry