* You could try this code.
* Right-click on the desired sheet tab and put the code in the
sheet's class module.
* Change Range("A:A") to reflect your needs.


Private Sub Worksheet_Change(ByVal Target As Excel.Range)
Dim rngISect As Range

Set rngISect = Intersect(Target, Range("A:A"))

On Error Resume Next
If Not rngISect Is Nothing And Target.Value <> "" Then
Application.EnableEvents = False
Target.Value = UCase(Target.Value)
Application.EnableEvents = True
End If

End Sub