Log ud funktion - men hvordan?

Jeg har implementeret dette login på min side....

<%
SET RS = Server.CreateObject("ADODB.Connection")
rs.Open "Driver={Microsoft Access Driver (*.mdb)}; DBQ=" & Server.MapPath("usersystem.mdb")

If Request("mode") = "Check" then

    ' Authes user, password, and fixed a known securitybug to many login systems.
        strUsername = Trim(Replace(request("username"),"'","''" ))
        strPassword = Trim(Replace(request("password"),"'","''" ))

  Sql = "Select Count(*) as Found from users where (username = '" & strUsername  & "') and (password ='" & strPassword  & "')"
  Set LO = RS.Execute(Sql)
  if LO("Found") = 0 then
    Session("login") = ""
    error = "You´re not authed be the system"
  else
  strDSN = "DRIVER={Microsoft Access Driver (*.mdb)};DBQ=" & Server.MapPath("usersystem.mdb")
  Set myConn = Server.CreateObject("ADODB.Connection")
  myConn.Open strDSN
  strSQL = "SELECT * FROM users where (username = '" & Request("username") & "') and (password ='" & Request("password") & "')"
  Set ez = myConn.Execute(strSQL)
    Session("login") = "Authed"
    Response.Redirect "http://www.graphical.dk/admin/default2.asp"
    EZ.Close
    RS.Close
    Conn.Close
  End if
End if
%>


MEN hvordan kan jeg lave en logud funktion?