Having trouble with plugin code in loop…

Hey Guys, Having trouble implementing a slideshow into my custom page template. When I put <?php if (have_posts()) : while (have_posts()) : the_post();?> into the page the bottom page content no longer displays. Does anyone know how I can get this to work. Thanks.

Here is the code I’m using to display the content of page:

<div id="main_ss">

                            <?php if ( function_exists('show_nivo_slider') ) { show_nivo_slider(); } ?>

                        </div>
                    </div>

                </div>

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

                        <div class="entry">

                            <?php the_content(); ?>

                        </div>

                    <?php endwhile; endif; ?>