Macro that AUTOMATICALLY activates another macro without human interference? HELP

Private Sub Workbook_Open()
If Weekday(Now, vbMonday) < 6 Then
    Application.OnTime VBA.TimeValue("23:59:00"), "knappen"
End If
End Sub

shall be in thisworkbook code. In VBA Editor (Alt+F11) click on the list of your workbook objects on ThisWorkbook (could be also translated - in PL versions since Excel 2007 it's called Then_Skoroszyt - which means thisworkbook anyway :-P) to open it's code

PS. To attach a sample workbook click on GO ADVANCED and then scroll down to Manage Attachments to open the upload window. Select files (max 2) press Upload and press Close then Submit reply