WP enqueue problem

Paste 1:
<script type="text/javascript" src="<?php echo get_stylesheet_directory_uri(); ?>/js/jquery-1.8.3.js"></script>
<script type="text/javascript" src="<?php echo get_stylesheet_directory_uri(); ?>/js/menu.js" ></script>
<script type="text/javascript" src="<?php echo get_stylesheet_directory_uri(); ?>/js/jquery.kwicks.js"></script>

Paste 2:
function load_my_scripts() {
        wp_deregister_script( 'jquery' );
        wp_register_script('jquery', '//ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js');
        wp_enqueue_script('jquery');
        wp_register_script('menu', get_stylesheet_directory_uri().'/js/menu.js', array('jquery') );
        wp_enqueue_script('menu');
        wp_register_script('kwicks', get_stylesheet_directory_uri().'/js/jquery.kwicks.js', array('jquery') );
        wp_enqueue_script('kwicks');
        wp_register_script('equalheights', get_stylesheet_directory_uri().'/js/jquery.equalheights.js', array('jquery') );
        wp_enqueue_script('equalheights');
}

add_action('wp_enqueue_scripts', 'load_my_scripts');

Paste 3:
function mainmenu(){
$(" #main_menu ul ").css({display: "none"}); // Opera Fix
$(" #main_menu li").hover(function(){
        $(this).find('ul:first').css({visibility: "visible",display: "none"}).show(400);
        },function(){
        $(this).find('ul:first').css({visibility: "hidden"});
        });
}

 function mainmenuWP(){
$(" #menu-mainmenu ul ").css({display: "none"}); // Opera Fix
$(" #menu-mainmenu li").hover(function(){
        $(this).find('ul:first').css({visibility: "visible",display: "none"}).show(400);
        },function(){
        $(this).find('ul:first').css({visibility: "hidden"});
        });
}


 $(document).ready(function(){
    alert("menu");
    mainmenu();
    mainmenuWP();
});