1. Open Excel 2007 and select the 'Office' button. Select 'Excel Options.' The Excel Options dialog box appears.
2. Select the 'Save' option on the left side of the Excel Options dialog box. Select 'Excel 97 -- 2003 Workbook' in the 'Save Files in this format. Click 'OK.'
3. Click the 'New' icon on the Quick Access Toolbar. A new Excel 2007 workbook opens displaying the Excel 2003 compatibility mode message.