Add date that row was modified.

I am trying to add the date to "column A" when ever a row is modified.

If i put this in a new workbook it works fine, but when added to my current work book it does nothing (not even a error)

Private Sub Worksheet_Change(ByVal Target As Range) 
    If Target.Row > 1 Then Cells(Target.Row, "A") = Now() 
End Sub 

I have tried on 2 different sheets and same issue. I re-saved the document as a macro enabled document but still same result. Can someone please tell why it does not work or how I can find out what the error is?