File download problem Urget help needed

I have problem in the following code. The file is downloaded but the webpage is not updated. After sending the file I want to hide a panel and show sonme other panel, which is not working.
Try         Path = GetFilePath()         Path = Server.MapPath(Path)         Response.Clear()         Dim fname As String = Path.Substring(Path.LastIndexOf("\") + 1)         Response.AddHeader("Content-Disposition", "attachment;filename=" & fname)         Response.ContentType = "application/zip"         Response.TransmitFile(Path)         ApplicationInstance.CompleteRequest()           ' ...