From setting in admin panel enable xmlrpc. that's all In windows live writer set your user id and password.
my problem is : I can not write the correct code for remote posting my web address for my blog. http://<hostname>/<wp_path>/xmlrpc.php I wrote many codes but It say Invalid URL or It is unavailable!!
You don't need to 'write codes' anywhere in Wordpress. Just go to Wordpress > Settings and place check mark on 'XML-RPC Protocol'.
I checked mark it before all process and typed my web name but it mentioned : 503 service unavailable !