UpdateProgress with a Response.Redirect

I have an UpdateProgress control to activate on a postback of a LinkButton control in UpdatePanel.  The LinkButton_click event is performing a Response.Redirect to pull up a Downloading.   The Download comes up and the UpdateProgress bar is spinning on the page with the button.  Either cancel downloading the UpdateProgress image is still there spinning. 

1- How can I make the UpdateProgress bar to finish and go away?

2- How can Freez page while spinning loding?

My code is

 protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
    {
        if (e.CommandName == "Downloads")
        {

            int index = int.Parse(e.CommandArgument.ToString());
            GridViewRow  selectedRow = GridView1.Rows[index];
            string cid = selectedRow.Cells[1].Text;
            DownloadFile();
        }

public void DownloadFile()
    {
        string directoryString = Session.SessionID;
         DirectoryInfo folder = Directory.CreateDirectory(directoryString);
        foreach (FileInfo file in folder.GetFiles())
        { file.Delete(); }

..
.
.
        string ss = GridView2.Rows[0].Cells[1].Text;
        string s = GridView2.Rows[0].Cells[2].Text;
        string filename_path = "D:\\VLS\\" + s + "\\" + ss;
        if (File.Exists(filename_path))
        {
            lberror.Visible = false;
            string filename = filename_path;
                          
               System.Threading.Thread.Sleep(1000);
 Response.Redirect("downloading.aspx?folder=" + directoryString + "&file=" + fname + "&DownloadName=" + ss);
         }
        else
        {
            lberror.Visible = true;
            lberror.Text = "File does not exist";


        }


    }

Thanks,