Microsoft Office Excel is a spreadsheet program. Microsoft released the first version of Excel for Windows in 1987. Since then, 10 more versions have appeared. As a rule, Microsoft Excel is backward compatible; a newer program version can always open previous version files. However, an older Excel release may not work with documents created with subsequent software versions. You can determine the Excel file version either from the file extension or file properties.
Click on the Windows "Start" button then on "Computer" to open Windows Explorer.
Browse your computer to find the Excel file.
Check the file extension. If it is ".xlsx" then the file was created with Excel 2007. The extension ".xls" indicates older program versions.
Right-click on the Excel file and choose "Properties" from the pop-up menu.
Select the tab "Details" (in Windows Vista or 7) or "Summary" then "Advanced" (in Windows XP).
Read the Excel version in the line "Type," for example, "Microsoft Office Excel 2003."