Date Reminder

Hi everyone

Im trying to get Excel to remind me on workbook open if a date is a 2 days past the recorded date.

for example in cell A12 i will have a datestamp of the 16 September 2012

and i want it to remind me if im 2 days overdue

Private Sub Workbook_Open()
    Dim Msg As String
    Dim Msg1 As String
    If Range("A12") = TODAY + 2 Then
        Msg = " Overdue"
        MsgBox Msg
    Else
        Msg1 = "not overdue"
        MsgBox Msg1
      End If
End Sub

This code always returns "not overdue" and i cannot get it to display the "overdue" message.

can anyone help to correct it please?

much appreciated