Module Module1
    WithEvents Timer1 As New Timers.Timer
    Dim exitFlag As Boolean = False
    Private Sub Timer1_Elapsed(ByVal sender As Object, ByVal e As System.Timers.ElapsedEventArgs) Handles Timer1.Elapsed

        'Если в файле flag.txt "0", то приложение прекращает работу
        Dim aFile As New IO.FileStream(Application.StartupPath & "\flag.txt", IO.FileMode.Open)
        Dim srSettingsIni As New IO.StreamReader(aFile, System.Text.Encoding.Default)

        If srSettingsIni.ReadLine() = "0" Then
            Timer1.Stop()
            exitFlag = True
        End If

        srSettingsIni.Close()
    End Sub

    Sub Main()
        Application.Run(Form1)

        Timer1.Interval = 5000
        Timer1.Start()

        While exitFlag = False
            Application.DoEvents()
        End While

        MsgBox("Завершение Main")
    End Sub
End Module