Making a File Open and asking the user to Save
FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
BinaryReader br = new BinaryReader(fs);
byte[] fileRD = br.ReadBytes((int)fs.Length);
br.Close();
fs.Close();
Response.AddHeader("Content-Disposition", "attachment;filename=\"" + strfilename + "\"");
Response.BinaryWrite( fileRD );
Response.End();