"right Click" on excel file in email, choose "save to",  then save to desktop.

Once on desktop, right click and choose "OPEN WITH" which opens an available program then choose "excel" (which ever version you have)

If you can't get that to work...

again right click on excel program on desktop, choose *properties*,, a dialog box will open, choose *excel* then choose *save changes* then open with your excel program.

To the best of my knowledge, excel is compatible back to at least Office 2000..