have_posts() needs a WordPress database query before it will show anything, check it here like this:
$the_query = new WP_Query( 'post_type=post' );
if ( $the_query->have_posts() ) {
echo '<ul>';
while ( $the_query->have_posts() ) {
$the_query->the_post();
echo '<li>' . get_the_title() . '</li>';
}
echo '</ul>';
} else {
// no posts found
}
it will display all posts in your blog.