You have to edit the navbar template (using the Styles & Templates admin)
Just remove this piece of code:
HTML Code:
<td class="vbmenu_control"><a href="search.php?$session[sessionurl]do=getnew" accesskey="2">$vbphrase[new_posts_nav]</a></td>
And this piece of code:
HTML Code:
<if condition="$show['member']">
<td id="usercptools" class="vbmenu_control"><a href="$show[nojs_link]#usercptools">$vbphrase[quick_links]</a> <script type="text/javascript"> vbmenu_register("usercptools"); </script></td>
</if>