Forcing Input to Uppercase

I wish to force data entry in cell C15 to upper case and have used the following code. (which I found on your site).

Private Sub Worksheet_SelectionChange(ByVal Target As Range)

    If Not (Application.Intersect(Target, Range("C15")) Is Nothing) Then 
   
     	  With Target   
    
           		 Application.EnableEvents = False

           		 Target = UCase(Target.Cells(1)) 
       
           		 Application.EnableEvents = True    
     
       	End With     
     
   End If

End Sub

When I exit the cell nothing has changed but, if I click again in cell C15 the entry changes to Upper case. Why and how can I fix it please?

Skin