NEL FORM1:

Private Sub MenuItem1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MenuItem1.Click
Dim obj_form2 As New Form2()
obj_form2.Show()
End Sub

NEL FORM2:

Dim obj_form1 As New Form1()
obj_form1.Close()

non chiude assolutamente nulla...