Need help in DirectoryInfo.GetDirectories

For Each drvInfo As IO.DriveInfo In IO.DriveInfo.GetDrives
            If drvInfo.IsReady Then
                Select Case drvInfo.DriveType
                    Case IO.DriveType.Fixed
                        Dim aNode As TreeNode = New TreeNode
                        aNode.Text = IIf(drvInfo.VolumeLabel <> "", drvInfo.VolumeLabel, "Local Disk") & "(" & drvInfo.Name.Replace("\", "") & ")"
                        aNode.Tag = drvInfo.Name.Replace("\", "")
                        tvwFolders.Nodes.Add(aNode)
                        gatherSubDir(aNode, drvInfo.Name.Replace("\", ""))
                    Case IO.DriveType.Removable
                        Dim aNode As TreeNode = New TreeNode
                        aNode.Text = IIf(drvInfo.VolumeLabel <> "", drvInfo.VolumeLabel, "Removable Disk") & "(" & drvInfo.Name.Replace("\", "") & ")"
                        aNode.Tag = drvInfo.Name.Replace("\", "")
                        tvwFolders.Nodes.Add(aNode)
                        gatherSubDir(aNode, drvInfo.Name.Replace("\", ""))
                End Select
            End If
        Next

' gatherSubDir routine
Private Sub gatherSubDir(ByVal node As TreeNode, ByVal dirName As String)
        Dim dInfo As IO.DirectoryInfo = New IO.DirectoryInfo(dirName)
        For Each anInfo As IO.DirectoryInfo In dInfo.GetDirectories
            Try
                If Not anInfo.Attributes And IO.FileAttributes.Hidden Then
                    Dim aNode As TreeNode
                    aNode = New TreeNode
                    aNode.Text = anInfo.Name
                    aNode.Tag = anInfo.FullName
                    node.Nodes.Add(aNode)
                    gatherSubDir(aNode, anInfo.FullName)
                End If
            Catch ex As Exception
            End Try
        Next
    End Sub

>Dim Files() As String = System.IO.Directory.GetFiles("D:\", "*.* ", IO.SearchOption.AllDirectories)
       Dim Filename As String
       For Each Filename In Files
magbox(Filename)
Next

////////////////////////////////////////////////////
public class FolderInfo
{
    public string Name       { get; set; }
    public bool AccessDenied { get; set; }
}

///////////////////////////////////////////////////
public class FolderList : List<FolderInfo>
{
    public int IndexOf(string name)
    {
        int index = -1;
        for (int i = 0; i < this.Count; i++)
        {
            if (this[i].Name.ToUpper() == name.ToUpper())
            {
                index = i;
                break;
            }
        }
        return index;
    }
}

///////////////////////////////////////////////////
public partial class MyForm
{
    FolderList m_folders = new FolderList();

    public MyForm()
    {
        InitializeComponents();
        GetDirectories(@"C:\");
    }

    private void GetDirectories(string path)
    {
        if (m_folders.IndexOf(path) < 0)
        {
            m_folders.Add(new FolderInfo(){Name=path, AccessDenied=false});
        }
        try
        {
            DirectoryInfo dirInfo = new DirectoryInfo(path);
            DirectoryInfo[] folders = dirInfo.GetDirectories("*.*", SearchOption.TopDirectoryOnly);
            for (int i = 0; i < folders.Length; i++)
            {
                if (!folders[i].Name.StartsWith("$"))
                {
                    GetDirectories(folders[i].FullName);
                }
            }
        }
        catch(Exception ex)
        {
            m_folders[m_folders.IndexOf(path)].AccessDenied = true;
        }
    }
}