TIMER DENTRO DO SUB MAIN

[ô]~~> The trick is to keep Sub Main running until the program is ready to exit.
[ô]~~> The program starts an API timer and then enters a DoEvents loop. When the
[ô]~~> variable m_Running is False, the program ends the loop, kills the timer, and exits. 
Private m_TimerID As LongPrivate m_Running As Boolean 
Private Sub Main()    [ô]~~> Start the timer.    
m_TimerID = SetTimer(0, 0, 3000, AddressOf MyTimer)     [ô]~~> Run until the timer sets m_Running to False.   
m_Running = True    
Do While m_Running        
DoEvents    
Loop     [ô]~~> Stop the timer.    
KillTimer 0, m_TimerID
End Sub 
[ô]~~> When the timer fires, the program asks the user if
[ô]~~> it should continue. If it should not, the program sets m_Running to False. 
Public Sub MyTimer(hwnd As Long, msg As Long, idTimer As _Long, dwTime As Long)    
Static i As Integer    
Static messagebox_visible As Boolean     
[ô]~~> Do nothing if another timer event is currently    
[ô]~~> displaying the message box.    
If messagebox_visible Then Exit Sub     
messagebox_visible = True    
i = i + 1        
If MsgBox(i & [Ô]: Stop?[Ô], vbYesNo) = vbYes Then _    
m_Running = False        
messagebox_visible = False
End Sub