Option Explicit
 
' alle benötigten API-Deklarationen
Private Declare Function SetTimer Lib "user32" _
  (ByVal hWnd As Long, ByVal nIDEvent As Long, _
   ByVal uElapse As Long, ByVal lpTimerFunc As Long) As Long
 
Private Declare Function KillTimer Lib "user32" _
  (ByVal hWnd As Long, ByVal nIDEvent As Long) As Long
 
Private Declare Function GetDesktopWindow Lib "user32" () As Long
Public Sub StartTimer(ByVal hWnd As Long, _
  ByVal lInterval As Long)
 
  ' Ist kein Formular vorhanden (hWnd = 0), so
  ' nehmen wir einfach das Handle des Desktop-Fenster
  If hWnd = 0 Then hWnd = GetDesktopWindow()
 
  ' Timer starten:
  ' Interval-Angabe in Millisekunden
  SetTimer hWnd, 0, lInterval, _
    AddressOf TimerProc
End Sub
Sub TimerProc(ByVal hWnd As Long, ByVal nIDEvent As Long, _
  ByVal uElapse As Long, ByVal lpTimerFunc As Long)
 
   MsgBox "Hallo"
 
End Sub
Public Sub KillTheTimer(ByVal hWnd As Long)
  ' WICHTIG! Timer killen, bevor die
  ' Anwendung beendet wird
 
  If hWnd = 0 Then hWnd = GetDesktopWindow()
  KillTimer hWnd, 0
End Sub

Option Explicit
 
Private Sub Form_Load()
Module1.StartTimer Me.hWnd, 1000
End Sub
 
Private Sub Form_Unload(Cancel As Integer)
Module1.KillTheTimer Me.hWnd
End Sub