Pages and posts displaying same post

Sorry about the title. This is a little confusing.

I recently altered my index page so the home page should only display the most recent post. Here’s some code:

<div class="post">
		<?php query_posts('showposts=1'); if (have_posts()) : while (have_posts()) : the_post();?>
		<h2><?php the_title(); ?></h2>
		<h4>Posted on <?php the_time('F jS, Y') ?></h4>
		<p><?php the_content(__('(more...)')); ?></p>
		<?php endwhile; else: ?>
		<p><?php _e('Sorry, no posts matched your criteria.'); ?></p>
		<?php endif; wp_reset_query(); ?>
	</div>

It works fine, but now, if I go to the page for a different post or a test page I made, they are ALL displaying THAT post.

Oh, this is offline, by the way.

Help? 🙁