/wp-content/themes/news/404.php

<?php
/**
 * 404 Template
 *
 * The 404 template is used when a reader visits an invalid URL on your site. By default,
 * the template will display a generic message. However, if the '404 Template' widget area
 * is active, its widgets will be displayed instead. This allows users to customize their error
 * pages in any way they want.
 *
 * For more information on how WordPress handles 404 errors:
 * @link http://codex.wordpress.org/Creating_an_Error_404_Page
 *
 * @package News
 * @subpackage Template
 */

@header( 'HTTP/1.1 404 Not found', true, 404 );

get_header(); ?>

	<?php do_atomic( 'before_content' ); // Before content hook ?>

	<div id="content">

		<?php do_atomic( 'open_content' ); // Open content hook ?>

		<div class="hfeed">

			<?php if ( is_active_sidebar( 'error-404-template' ) ) : ?>

				<div id="sidebar-error-404" class="sidebar utility">
					<?php dynamic_sidebar( 'error-404-template' ); ?>
				</div><!-- #sidebar-error-404 .utility -->

			<?php else: ?>

				<div id="post-0" class="<?php hybrid_entry_class(); ?>">

					<h1 class="error-404-title entry-title"><?php _e( 'Not Found', 'news' ); ?></h1>

					<div class="entry-content">

						<p>
						<?php printf( __( 'You tried going to %1$s, and it doesn\'t exist. All is not lost! You can search for what you\'re looking for.', 'news' ), '<code>' . home_url( esc_url( $_SERVER['REQUEST_URI'] ) ) . '</code>' ); ?>
						</p>

						<?php get_search_form(); ?>

					</div><!-- .entry-content -->

				</div><!-- .hentry -->

			<?php endif; ?>

		</div><!-- .hfeed -->

		<?php do_atomic( 'close_content' ); // Close content hook ?>

	</div><!-- #content -->

	<?php do_atomic( 'after_content' ); // After content hook ?>

<?php get_footer(); ?>