function fb_filter_query( $query, $error = true ) { 
 
if ( is_search() ) { 
$query->is_search = false; 
$query->query_vars[s] = false; 
$query->query[s] = false; 
// to error
>if ( $error == true ) 
$query->is_404 = true; 
} 
} 
add_action( 'parse_query', 'fb_filter_query' ); 
add_filter( 'get_search_form', create_function( '$a', "return null;" ) );