An alternate solution, using formulas instead of VBA, is to set up a second sheet to mirror your first sheet and use the =UPPER() formula. Say, for instance, the range on sheet 1 you want to upper-case is A1 thru F15. Go to sheet 2, and, in cell A1, enter the formula =UPPER(Sheet1|A1). Copy this formula to A2 thru A15 and then from A1:A15 to B1:F15.
Advantage to this is that you can enter new info or edit info on sheet 1 (within that range) and you don't have to run a macro to update to upper-case, it is automatically reflected on sheet 2.