Private Declare Function CreateEllipticRgn Lib "gdi32" _
        (ByVal X1 As Long, ByVal Y1 As Long, ByVal X2 As _
        Long, ByVal Y2 As Long) As Long
 
    Private Declare Function SetWindowRgn Lib "user32.dll" ( _
                 ByVal hWnd As Long, _
                 ByVal hRgn As Long, _
                 ByVal bRedraw As Boolean) As Long
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        Dim Region As Long
 
        Region = CreateEllipticRgn(0, 0, Me.Width - 1, Me.Height - 1)
        SetWindowRgn(Me.Handle, Region, True)
    End Sub