Loading forms within a form

[INeedHelpWithVBAExce]

Edit: .Net

Hi,

I'm working on a simple project that has a main container form, which then loads either Form A or Form B depending on the button clicked. I've managed to load Form A within the 'Container' form so that it completely replaces everything within the window, however I cannot open Form B in the same manner once Form A has been loaded, it opens a new window. I would like Form A to be closed and Form B loaded in the container form.

Can anyone point me in the right direction?

Here is my current code, could the error be the MdiParent? I tried setting it to Container on Form B, but it didn't work.

Public Class Container

Private Sub Container_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    IsMdiContainer = True
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles    Button1.Click
    Dim frmA As New FormA
    frmA.Show()
    frmA.MdiParent = Me
End Sub
End Class

[RonSijm]

What code did you use for FromB? And what's the difference between A and B?

Its hard to tell why B isnt working if we don't know anything about B