Private Const LWA_ALPHA = &H2
  Private Const WS_EX_LAYERED = &H80000
  Private Const GWL_EXSTYLE = -20

  Private Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongW" _
   (ByVal hwnd As IntPtr, ByVal nIndex As Integer, ByVal dwNewLong As Integer) As Integer
  Private Declare Function GetWindowLong Lib "user32" Alias _
   "GetWindowLongW" (ByVal hwnd As IntPtr, ByVal nIndex As Integer) As Integer
  Private Declare Function SetLayeredWindowAttributes Lib "user32" _
   (ByVal hwnd As IntPtr, ByVal crKey As Integer, ByVal bAlpha As Byte, ByVal dwFlags As Integer) As Boolean

  Private Sub Form_Load(ByVal sender As Object,
                             ByVal e As System.EventArgs) Handles Me.Load
    Call SetWindowLong(Me.Handle, GWL_EXSTYLE, _
     GetWindowLong(Me.Handle, GWL_EXSTYLE) Or WS_EX_LAYERED)
    Call SetLayeredWindowAttributes(Me.Handle, 0, 0, LWA_ALPHA) 'полностью прозрачна
    TimerAlpha.Interval = 1
    TimerAlpha.Enabled = True
  End Sub

  Private Sub TimerAlpha_Tick(ByVal sender As System.Object,
                              ByVal e As System.EventArgs) Handles TimerAlpha.Tick
    Call SetLayeredWindowAttributes(Me.Handle, 0, 255, LWA_ALPHA) 'полностью НЕпрозрачна
    TimerAlpha.Enabled = False
  End Sub