Site Heading is a link/underlined

Edit your header.php file. There should be some code in it that looks something along the lines of:

<h1><a href="<?php bloginfo('url'); ?>/"><?php bloginfo('name'); ?></a></h1>

Get rid of the link tags from that, so it becomes more like:

<h1><?php bloginfo('name'); ?></h1>

Your actual code will probably vary slightly.