How to open run a file after user save the file with savefiledialog

saveFileDialog1.OpenFile();

public void checkForUpdate()
       {
           //Update From Website.
           string URL = "http://pingmanager.ir/program/";
           string AppName = saveFileDialog1.FileName = "PingManager.msi";
           string ServerVersion;
           string serverVersionName = "version.txt";
           string Flname = "PingManager.msi";


           // Request
           WebRequest req = WebRequest.Create(URL + serverVersionName);
           WebResponse res = req.GetResponse();
           Stream str = res.GetResponseStream();
           StreamReader tr = new StreamReader(str);
           ServerVersion = tr.ReadLine();

           if(getVersion() != ServerVersion)
           {
               //Update.
               WebClient client = new WebClient();
               byte[] appdata = client.DownloadData(URL + AppName);

               // Message for Update Available.
               MessageBox.Show("Update is Available.", "PingManager",
               MessageBoxButtons.OK, MessageBoxIcon.Warning);

               // Save the New Version of Program From Website.
               if (saveFileDialog1.ShowDialog() == DialogResult.OK)
               {
                   // Save Name of Setup File.
                   using (FileStream fs = File.Create(saveFileDialog1.FileName))
                   {
                       fs.Write(appdata, 0, appdata.Length);
                       saveFileDialog1.OpenFile();
                   }

                   // Message of The New Version of Setup Downloaded.
                   MessageBox.Show("Update File Compeleted.", "PingManager",
                   MessageBoxButtons.OK, MessageBoxIcon.Information);

               }


               this.Close();