Function IsValidUser(usr, pwd)  
     Dim Conn,  RS,  SQL
     Set Conn = Server.CreateObject("ADODB.Connection")
     Conn.Open ("DRIVER={Microsoft Access Driver "& _
          " (*.mdb)};DBQ=C:\databases\users.mdb")
  
     SQL = "SELECT COUNT(UserName) FROM Users WHERE "& _
                " UserName= '"&   usr & "' AND Password= "' & pwd & "'"
  
     Set RS = Conn.Execute(SQL)
     If Not RS.EOF  Then
        If  CInt(RS(0)) = 1  Then
            IsValidUser =  True
        End  If
        RS.Close
     End  If
     Set RS =  Nothing
  End  Function

<users>
    <john role="admin">pass1</john>
    <jen role="user">pass2</jen>
    <joey role="usre">pass3</joey>
</users>

Function IsValidUser(usr,  pwd)  
     'reset all variables
     IsValidUser =  False
     Session("UserRole") = ""
        
     'On Error Resume Next
      Dim xmldoc, nodeList, node
      Set xmldoc = Server.CreateObject("Microsoft.XMLDOM")
     xmldoc.async =  False
  
             'xmldoc.load(Server.MapPath("users.xml"))
     xmldoc.load("D:\secure\users.xml")      
      
      If xmldoc.parseError.ErrorCode=0  Then
           Set nodeList = xmldoc.documentElement.getElementsByTagName(usr)
           If nodeList.length>0  Then
                If nodeList.Item(0).Text = pwd  Then
                    IsValidUser =  True
                     On  Error  Resume Next                     
                    Session("UserRole") = nodeList.Item(0).attributes.getNamedItem("role").nodeValue
                     If Err.number<>0  Then
                         Session("UserRole") = "GUEST"
                     End  If
                End  If
           End  If
      End  If
      Set xmldoc =  Nothing
  End  Function