Private TIMERID As Long
 
Private Sub Command1_Click()
   TIMERID = Module1.StartMMTimer(1)
End Sub
 
Private Sub Command2_Click()
   Module1.KillMMTimer TIMERID
   TIMERID = 0
End Sub
 
Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
   If TIMERID <> 0 Then Module1.KillMMTimer TIMERID
End Sub

Private Const TIME_ONESHOT As Long = 0
Private Const TIME_PERIODIC As Long = 1
 
Private Declare Function timeSetEvent Lib "winmm.dll" ( _
     ByVal uDelay As Long, _
     ByVal uResolution As Long, _
     ByVal lpFunction As Long, _
     ByVal dwUser As Long, _
     ByVal uFlags As Long) As Long
 
Private Declare Function timeKillEvent Lib "winmm.dll" ( _
     ByVal uID As Long) As Long
 
Public Sub KillMMTimer(ByVal nID As Long)
   timeKillEvent nID
End Sub
 
Public Function StartMMTimer(ByVal nMillisekonds As Long) As Long
   StartMMTimer = timeSetEvent(nMillisekonds, 1, AddressOf OneShotTimer, 0, _
               TIME_PERIODIC)
End Function
 
Private Sub OneShotTimer(ByVal wTimerID As Long, ByVal msg As Long, _
    ByVal dwUser As Long, ByVal dw1 As Long, ByVal dw2 As Long)
   Static n
   n = n + 1
   Form1.Caption = n
End Sub