求助，连接问题

<!--#include file="conn.asp"-->
<!--#include file="../inc/md5.asp"-->
<%
    dim mSql,rs
   
       mUserName=Trim(Request.Form("user"))
    mPassword=md5(Trim(Request.Form("psw")))
    Sql="Select name,psw,xk from jsid Where  name= '"&mUserName&"'"
    set rs = server.createobject("adodb.recordset")
     rs.open sql,conn,1,1
         if rs.bof and rs.eof then
            response.write "<script>alert('对不起，该用户不存在！');history.back();</Script>"
                    response.end            
     else
        if mPassword<>rs("psw") then
                response.write "<script>alert('对不起，请输入正确的口令。！');history.back();</Script>"
        else
              session("nameuse")=mUserName
                          session("xueke")=rs("xk")
              Response.Redirect "main.asp"
        end if
            
            
     end if
    rs.close
    set rs=nothing
%>

我输入正确的用户名，可提示“对不起，该用户不存在！” 不知什么原因，请高手指教