Private Sub Worksheet_Change(ByVal Target As Range)
    Application.EnableEvents = False
    Dim result As String
    With Target
        If (.Column = 2 Or .Column = 6) And .Row <> 1 _
            And Not IsNumeric(.Value) And Not IsEmpty(.Value) Then
            For i = 1 To Len(.Value)
                MyChar = Mid(.Value, i, 1)
                MyChrCode = Asc(MyChar)
                If MyChar = "." Or MyChrCode >= 48 And MyChrCode <= 57 Then
                    result = result & MyChar
                ElseIf MyChar = "," Or MyChar = ":" Then
                    result = result & "."
                End If
            Next i
        On Error Resume Next
        .Value = CDate(result)
        If Err.Number <> 0 Then
                .ClearContents
        Else
            .NumberFormat = "m/d/yyyy"
        End If
        Application.EnableEvents = True
      End If
    End With
End Sub