Note that Winforms does not allow child controls to actually be transparent. As others have posted a separate transparent window is possible - but messy to manage.

Cheap way

• drag all controls into one panel and make it the size of the window (easy change)
• When operating: Hide that panel. Use the panels .DrawToBitmap method to set form background image.
• show progress bar, do work with 'doevents,' hide it.
• clear background image, re-show panel.

A Better way:

Progress Class - Consumer

I will give you a Usercontrol I wrote and have used in many different programs that does exactly what you want. Here is a trivial consumer example, you can paste into a form's code (yes, it just makes a bunch of new buttons for no reason):

Public Class Form1

    Private Sub Form1_FormClosed(ByVal sender As Object, ByVal e As System.Windows.Forms.FormClosedEventArgs) Handles Me.FormClosed
        End ''// use a flag if you would like a more graceful way to handle this. 
    End Sub

    WithEvents ucProgress As New Progress   ''// just doing it this way so I don''//t have to paste designer code.

    Private Sub Form1_Shown(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Shown
        Controls.Clear()
        Controls.Add(ucProgress)
        Me.ucProgress.pb.Visible = False
        ucProgress.StartProgress()
        Try
            ucProgress.Message = "Starting up..."
            Application.DoEvents()
            Me.ucProgress.pb.Visible = True
            Me.ucProgress.pb.Maximum = 21
            Me.ucProgress.pb.Value = 0

            For i As Integer = 0 To 20
                Dim btn As New Button

                btn.Top = +i * 3
                btn.Left = i * 8
                btn.Text = CStr(i)
                btn.Enabled = False ''// ONLY HAVE TO DO FOR CTLS RIGHT ON MAIN FORM
                ucProgress.EnabledStates.Add(btn, True)  ''// ONLY HAVE TO DO FOR C