When i open a certain file i want that immediately a backup of this file is
saved to the same folder but with the date that the file was opened added.

Example : file name is "file1.xls".
When this file is opened on 16-dec, i want a backup saved under the name
"file1-16-dec-2010.xls"
When the file is opened a second or third,... time on the same day, then the
backup file "file1-16-dec-2010.xls"has to be overwritten whitout asking


Who can provide me with some code?

Thanks,

Luc