Save As Office
97-2003
When you save
a new spreadsheet in Microsoft Excel 2007 or Excel 2010, you should be
aware that this is a new file format and that companies with a previous
version of Microsoft Excel might not be able to open or edit your work.
Here are the steps you can take to create a copy in the Excel 97-2003
file format.
Try it: Save As Previous Version
Go to File ->Save As.
Keep going...