Regex reg1 = new Regex("Company/index\\.aspx\\u003FFid=([^&]*)&Sid=([^&]*)", RegexOptions.IgnoreCase);
Response.Write(" <br> <br> <br> <br> <br> <br>");
Response.Write(reg1.Replace("Company/index.aspx?Fid=123&Sid=456", "Company/Fid-$1-Sid-$2.htm"));
Response.Write(" <br> <br> <br> <br> <br> <br>");
Response.Write(reg1.Replace("Company/index.aspx?Fid=123&Sid=456", "Company/Fid-$1-Sid-$2.htm"));