Hi,
if you want to completely remove it you must delete <img element form index.php of template:
...
<div id="topmenu">
<div id="logo"><a href="index.php">
<img src="<?php echo $template_path ?>/images/logo<?php echo $templateStyle; ?>.png" width="228" height="126" alt="joomla furniture store" /></a></div>
<div id="topmenu_pad">
...
if you want to change it then you can find logo images in /images folder as
logo1.pnp,
logo2.png
...
depending on template style you use .
