VBA Script has stopped working

HI

I am using the following script which I found on the net but it seems to have stopped working. The workbook contains 52 spreadsheets and I have put this script on each one. It turns whatever is entered into capitals, we when it was working it did anyway.

Private Sub Worksheet_Change(ByVal Target As Range)
   If Target.HasFormula Then Exit Sub
   Target = UCase(Target)
End Sub

Any help would be apreciated.