How to fetch and show particular posts for a tag on home page in wordpress

[admin]

I am trying to fetch and show all posts in a featured listing style for tag

my-guide

<?php if(have_posts()) : ?><?php while(have_posts()) : the_post(); ?>
    <div class="post" id="post-<?php the_ID(); ?>">
    <div class="thumbnail">
    <a href="<?php the_permalink(); ?>">
    <?php the_post_thumbnail(); ?>
    </a>
    </div>
    <?php endwhile; ?>
    <?php endif; ?>

This code fetch all featured image from posts, however I am trying to fetch it via particular tag, I tried this also but its not working for tag

query_posts('tag=my-guide');

-

    <?php query_posts('tag=my-guide'); 
  while (have_posts()) : the_post();  
?>  
<div class="breaking">  
    <img src="<?php echo get_post_meta($post->ID, 'thumbnail',true) ?>" alt="Post Image" class="postimg" />  
    <h2><a href="<?php the_permalink() ?>" title="<?php the_title(); ?>"><?php the_title(); ?></a></h2>  
    <p class="datetime"><?php the_time('l, F j, Y G:i'); ?></p>  
    <?php the_content('Continue...'); ?>  
    <div class="postmeta">  
        <p><?php the_category(', '); ?> - <a href="<?php the_permalink() ?>#commenting" title="View Comments">  
    <span class="comm"><?php comments_number('0 Comments','1 Comment','% Comments'); ?></span></a></p>  
    </div><!--/postmeta-->  
</div><!--/breaking-->  
<?php endwhile; ?>

Source of this -> <a href="http://net.tutsplus.com/tutorials/wordpress/build-a-featured-posts-section-for-wordpress/" rel="nofollow">http://net.tutsplus.com/tutorials/wordpress/build-a-featured-posts-section-for-wordpress/</a>