Public Class Form1
    Inherits System.Windows.Forms.Form
 
#Region " Windows Form Designer generated code "
    Public Shared frm1 As Form1
    Public Shared frm2 As New Form2
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        frm1 = Me
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        frm2.Show()
        Me.Hide()
    End Sub
End Class

Public Class Form2
    Inherits System.Windows.Forms.Form
 
#Region " Windows Form Designer generated code "
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button1.Click
        Form1.frm1.Show()
        Me.Hide()
    End Sub
End Class