how to overcome this error. Access to the path 'C:\Documents and Settings' is denied.

private void button1_Click(object sender, EventArgs e)
      {

          foreach (string file in GetFiles("C:\\"))
          {
              //  Console.WriteLine(file);
              listBox2.Items.Add(file);
          }

}


      static IEnumerable<string> GetFiles(string path)
      {
          Queue<string> queue = new Queue<string>();
          queue.Enqueue(path);
          while (queue.Count > 0)
          {
              path = queue.Dequeue();
              try
              {
                  foreach (string subDir in Directory.GetDirectories(path))
                  {
                      queue.Enqueue(subDir);
                  }
              }
              catch (Exception ex)
              {
                   MessageBox.Show("ex");
                  Console.Error.WriteLine(ex);
              }
              string[] files = null;
              try
              {
                  files = Directory.GetFiles(path);
              }
              catch (Exception ex)
              {
                  Console.Error.WriteLine(ex);
              }
              if (files != null)
              {
                  for (int i = 0; i < files.Length; i++)
                  {
                      yield return files[i];

                  }
              }
          }
      }