StringBuilder sb= new StringBuilder();
sb.Append("<SCRIPT LANGUAGE='Javascript'>");
sb.Append("window.showModalDialog('blanktapebacktransfer.aspx','update','center=yes;status:no;help:no;scroll:no;dialogWidth:600px;DialogHeight:400px;center:Yes;')");
sb.Append("</SCRIPT>");
Page.RegisterStartupScript("msg", sb.ToString());