FolderPrincipal = Folder ' SE GUARDA EL DIRECTORIO EN LA VARIABLE PUBLICA

    Public Class Form2
 
    Dim Listita As New ListBox
 
    Private Sub Form2_Load(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Load
        With Listita
            .BackColor = Color.White
            .ForeColor = Color.Black
            .Size = New Point(340, 251)
            .Location = New Point(12, 25)
            AddHandler .SelectedIndexChanged, AddressOf Listita_SelectedIndexChanged
        End With
        Me.Controls.Add(Listita)
        if My.Settings.Folder isnot nothing then LoadFolder(My.Settings.Folder) ' Aquí cargas el último directorio que se cargó al salir de la aplicación
    End Sub
 
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Me.Hide()
    End Sub
 
    Private Sub Listita_SelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
        Dim Item As New IO.FileInfo(My.Settings.Folder & "\" & Listita.SelectedItem)
        MsgBox(Item.FullName)
    End Sub
 
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim FBD As New FolderBrowserDialog
        FBD.Description = " Seleccionar una carpeta "
        FBD.SelectedPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)
        FBD.ShowNewFolderButton = True
        If FBD.ShowDialog = Windows.Forms.DialogResult.OK Then : My.Settings.Folder = FBD.SelectedPath : LoadFolder(My.Settings.Folder) : End If
        FBD.Dispose()
    End Sub
 
    Private Sub LoadFolder(ByVal Folder As String)
        Try
            Listita.Items.Clear()
            Dim Files As Array = IO.Directory.GetFiles(Folder, "*")
            Dim TotalRoms As Int32 = Files.Length
            For Each File In Files
                Dim File_Info As New IO.FileInfo(File)
                Listita.Items.Add(File_Info.Name)
            Next
            Label1.Text = "Roms encontrados (" & TotalRoms & ")"
        Catch ex As Exception : MsgBox(ex.Message)
        End Try
    End Sub
 
    Private Sub Button4_Click(sender As Object, e As EventArgs) Handles Button4.Click
        MessageBox.Show(My.Settings.Folder, "", MessageBoxButtons.OK, MessageBoxIcon.Information, MessageBoxDefaultButton.Button1)
    End Sub
 
End Class

Edu me recomiendas que me quite el NET 2.0 y 3.5?