My site is pretty much like youtube with main video in the single.php and sidebar.php with related videos. However, currently when I clicked on "related video" in sidebar.php, the entire page refreshes. I've tried several ajax tutorials but without any luck.

What I would like to achieve is to click the "related videos" from sidebar.php and only the main video on single.php would refresh.

this is in single.php which displays the main video via "the_post()"
PHP Code:
<?php get_header(); ?>

    <div id="content">

        <div class="singlebody">

        <?php if (have_posts()) : while (have_posts()) : the_post(); ?>

            <div class="singlepost">

                <h2><?php the_title(); ?></h2>
here is the sidebar.php, I would like to ajax the link so that only main video will refreshes.
PHP Code:
while( have_posts() ) {
    foreach( ( get_the_category() ) as $category )
        $my_query = new WP_Query('category_name=' . $category->category_nicename . '&orderby=date&order=desc&showposts=100');
    if( $my_query ) {
        while ( $my_query->have_posts() ) {
            $my_query->the_post(); ?>

                        <a href="<?php the_permalink() ?>"  rel="bookmark" title="<?php the_title_attribute(); ?>"></a><?php the_title();?></div>