I don't know if this is what you want, but if you start Excel and go to
Tools | Options | Calculation (tab) you can set it to Manual, before
opening any files. Now any files that you do open will be in manual
calculation mode - you can get them to recalculate by pressing F9. If
you save the file, then a full recalculation is normally done (unless
you unchecked this in Tools | Options).