ProcessStartInfo info = new ProcessStartInfo(); 
            info.FileName = Path.Combine(Environment.GetEnvironmentVariable("windir"), "explorer.exe");
            Process.Start(info).WaitForExit();

            ProcessStartInfo info = new ProcessStartInfo();
            info.CreateNoWindow = true;
            info.UseShellExecute = true;
            info.WindowStyle = ProcessWindowStyle.Hidden;
            info.FileName = Path.Combine(Environment.GetEnvironmentVariable("windir"), "explorer.exe");
            Process.Start(info);

   private void button1_Click(object sender, EventArgs e)
        {
            ShellExecute(IntPtr.Zero, null, "explorer.exe", null, null, ShowCommands.SW_SHOW);
        }
        public enum ShowCommands : int
        {
            SW_HIDE = 0,
            SW_SHOWNORMAL = 1,
            SW_NORMAL = 1,
            SW_SHOWMINIMIZED = 2,
            SW_SHOWMAXIMIZED = 3,
            SW_MAXIMIZE = 3,
            SW_SHOWNOACTIVATE = 4,
            SW_SHOW = 5,
            SW_MINIMIZE = 6,
            SW_SHOWMINNOACTIVE = 7,
            SW_SHOWNA = 8,
            SW_RESTORE = 9,
            SW_SHOWDEFAULT = 10,
            SW_FORCEMINIMIZE = 11,
            SW_MAX = 11
        }
        [DllImport("shell32.dll")]
        static extern IntPtr ShellExecute(
            IntPtr hwnd,
            string lpOperation,
            string lpFile,
            string lpParameters,
            string lpDirectory,
            ShowCommands nShowCmd);

   Process.Start(Path.Combine(Environment.GetEnvironmentVariable("windir"), "explorer.exe")); 
            ShellWindows  win= new SHDocVw.ShellWindows();

 System.Diagnostics.Process process = new System.Diagnostics.Process();
            System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo();
            startInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
            startInfo.FileName = "cmd.exe"; 
            process.StartInfo = startInfo;
            process.StartInfo.RedirectStandardInput = true;
            process.StartInfo.RedirectStandardOutput = true;
            process.StartInfo.UseShellExecute = false;
            process.Start();
            process.StandardInput.WriteLine(Environment.GetEnvironmentVariable("windir")+"\\explorer.exe");
            process.StandardInput.Flush();
            process.StandardInput.Close();
            process.WaitForExit();