Admin CP -> Styles & Templates -> Style Manager -> Name of your Style -> Select "Edit Templates" from the dropdown menu.
Find "Navigation / Breadcrumb Templates", click on it... Then click on "navbar".
Select everything, and replace it with this:
<br />
<!-- breadcrumb, login, pm info -->
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<tr>
<td class="alt1" width="100%">
<if condition="is_array($navbits)">
<table cellpadding="0" cellspacing="0" border="0">
<tr valign="bottom">
<td><a href="#" onclick="history.back(1); return false;"><img src="$stylevar[imgdir_misc]/navbits_start.gif" alt="$vbphrase[go_back]" border="0" /></a></td>
<td> </td>
<td width="100%"><span class="navbar"><a href="$vboptions[forumhome].php$session[sessionurl_q]" accesskey="1">$vboptions[bbtitle]</a></span> $navbits[breadcrumb]</td>
</tr>
<tr>
<td class="navbar" style="font-size:10pt; padding-top:1px" colspan="3"><if condition="$_SERVER['REQUEST_METHOD'] == 'POST'"><img class="inlineimg" src="$stylevar[imgdir_misc]/navbits_finallink_$stylevar[textdirection].gif" alt="" border="0" /><else /><a href="$navbar_reloadurl"><img class="inlineimg" src="$stylevar[imgdir_misc]/navbits_finallink_$stylevar[textdirection].gif" alt="$vbphrase[reload_this_page]" border="0" /></a></if> <strong>$navbits[lastelement]</strong></td>
</tr>
</table>
<else />
<div class="navbar" style="font-size:10pt"><a href="$vboptions[forumhome].php$session[sessionurl_q]" accesskey="1"><img class="inlineimg" src="$stylevar[imgdir_misc]/navbits_start.gif" alt="" border="0" /></a> <strong>$vboptions[bbtitle]</strong></div>
</if>
</td>
<if condition="$show['member']">
<td class="alt2" nowrap="nowrap">
<div class="smallfont">
<strong><phrase 1="$bbuserinfo[username]" 2="member.php?$session[sessionurl]u=$bbuserinfo[userid]">$vbphrase[welcome_x_link_y]</phrase></strong><br />
<phrase 1="$pmbox[lastvisitdate]" 2="$pmbox[lastvisittime]">$vbphrase[last_visited_x_at_y]</phrase>
<if condition="$show['notifications']">
<div><span id="notifications"><a href="usercp.php$session[sessionurl_q]">$vbphrase[your_notifications]:</a> <strong>$notifications_total</strong></span></div>
<if condition="$show['popups']">
<script type="text/javascript"> vBmenu.register("notifications"); </script>
<else />
<script type="text/javascript" src="clientscript/vbulletin_notifications_nopopups.js?v=$vboptions[simpleversion]"></script>
<script type="text/javascript"> vBulletin.register_control("vB_Notifications_NoPopups", "notifications"); </script>
</if>
<else /><if condition="$show['pmstats']">
<div><phrase 1="$vbphrase[unread_x_nav_compiled]" 2="$vbphrase[total_x_nav_compiled]" 3="$session[sessionurl_q]">$vbphrase[private_messages_nav]</phrase></div>
</if></if>
<if condition="$show['pmwarning']"><div><strong><phrase 1="$vbphrase[pmpercent_nav_compiled]">$vbphrase[your_pm_box_is_x_full]</phrase></strong></div></if>
</div>
</td>
<else />
<td class="alt2" nowrap="nowrap" style="padding:0px">
<!-- login form -->
<form action="login.php?do=login" method="post" onsubmit="md5hash(vb_login_password, vb_login_md5password, vb_login_md5password_utf, $show[nopasswordempty])">
<script type="text/javascript" src="clientscript/vbulletin_md5.js?v=$vboptions[simpleversion]"></script>
<table cellpadding="0" cellspacing="$stylevar[formspacer]" border="0">
<tr>
<td class="smallfont" style="white-space: nowrap;"><label for="navbar_username">$vbphrase[username]</label></td>
<td><input type="text" class="bginput" style="font-size: 11px" name="vb_login_username" id="navbar_username" size="10" accesskey="u" tabindex="101" value="$vbphrase[username]" onfocus="if (this.value == '$vbphrase[username]') this.value = '';" /></td>
<td class="smallfont" nowrap="nowrap"><label for="cb_cookieuser_navbar"><input type="checkbox" name="cookieuser" value="1" tabindex="103" id="cb_cookieuser_navbar" accesskey="c" />$vbphrase[remember_me]</label></td>
</tr>
<tr>
<td class="smallfont"><label for="navbar_password">$vbphrase[password]</label></td>
<td><input type="password" class="bginput" style="font-size: 11px" name="vb_login_password" id="navbar_password" size="10" tabindex="102" /></td>
<td><input type="submit" class="button" value="$vbphrase[log_in]" tabindex="104" title="$vbphrase[enter_username_to_login_or_register]" accesskey="s" /></td>
</tr>
</table>
<input type="hidden" name="s" value="$session[sessionhash]" />
<input type="hidden" name="securitytoken" value="$bbuserinfo[securitytoken]" />
<input type="hidden" name="do" value="login" />
<input type="hidden" name="vb_login_md5password" />
<input type="hidden" name="vb_login_md5password_utf" />
</form>
<!-- / login form -->
</td>
</if>
</tr>
</table>
<!-- / breadcrumb, login, pm info -->
<!-- nav buttons bar -->
<div class="tborder" style="padding:$stylevar[cellspacing]px; border-top-width:0px">
<table cellpadding="0" cellspacing="0" border="0" width="100%" align="center">
<tr align="center">
<if condition="$show['member']">
<td class="vbmenu_control"><a href="usercp.php$session[sessionurl_q]">$vbphrase[user_cp]</a></td>
</if>
<if condition="$show['registerbutton']">
<td class="vbmenu_control"><a href="register.php$session[sessionurl_q]" rel="nofollow">$vbphrase[register]</a></td>
</if>
$template_hook[navbar_buttons_left]
<td class="vbmenu_control"><a rel="help" href="faq.php$session[sessionurl_q]" accesskey="5">$vbphrase[faq]</a></td>
<if condition="$show['memberslist']">
<td class="vbmenu_control"><a href="memberlist.php$session[sessionurl_q]">$vbphrase[members_list]</a></td>
</if>
<if condition="$show['quick_links_groups']">
<td class="vbmenu_control"><a href="group.php?$session[sessionurl]">$vbphrase[social_groups]</a></td>
</if>
<td class="vbmenu_control"><a href="calendar.php$session[sessionurl_q]">$vbphrase[calendar]</a></td>
<if condition="$show['popups']">
<if condition="$show['searchbuttons']">
<if condition="$show['member']">
<td class="vbmenu_control"><a href="search.php?$session[sessionurl]do=getnew" accesskey="2">$vbphrase[new_posts_nav]</a></td>
<else />
<td class="vbmenu_control"><a href="search.php?$session[sessionurl]do=getdaily" accesskey="2">$vbphrase[todays_posts]</a></td>
</if>
<td class="vbmenu_control"><a id="navbar_search" href="search.php$session[sessionurl_q]" accesskey="4" rel="nofollow">$vbphrase[search]</a> <if condition="$show['quicksearch']"><script type="text/javascript"> vbmenu_register("navbar_search"); </script></if></td>
</if>
<else />
<if condition="$show['searchbuttons']">
<td class="vbmenu_control"><a href="search.php$session[sessionurl_q]" accesskey="4">$vbphrase[search]</a></td>
<if condition="$show['member']">
<td class="vbmenu_control"><a href="search.php?$session[sessionurl]do=getnew" accesskey="2">$vbphrase[new_posts_nav]</a></td>
<else />
<td class="vbmenu_control"><a href="search.php?$session[sessionurl]do=getdaily" accesskey="2">$vbphrase[todays_posts]</a></td>
</if>
</if>
<td class="vbmenu_control"><a href="forumdisplay.php?$session[sessionurl]do=markread" rel="nofollow">$vbphrase[mark_forums_read]</a></td>
<if condition="$show['member']">
<td class="vbmenu_control"><a href="#" onclick="window.open('misc.php?$session[sessionurl]do=buddylist&focus=1','buddylist','statusbar=no,me nubar=no,toolbar=no,scrollbars=yes,resizable=yes,w idth=250,height=300'); return false;">$vbphrase[open_contacts]</a></td>
</if>
</if>
$template_hook[navbar_buttons_right]
<if condition="$show['member']">
<td class="vbmenu_control"><a href="login.php?$session[sessionurl]do=logout&logouthash=$bbuserinfo[logouthash]" onclick="return log_out('$vbphrase[sure_you_want_to_log_out]')">$vbphrase[log_out]</a></td>
</if>
</tr>
</table>
</div>
<!-- / nav buttons bar -->
<br />
<if condition="$show['notices']">
<form action="profile.php?do=dismissnotice" method="post" id="notices">
<input type="hidden" name="do" value="dismissnotice" />
<input type="hidden" name="securitytoken" value="$bbuserinfo[securitytoken]" />
<input type="hidden" id="dismiss_notice_hidden" name="dismiss_noticeid" value="" />
<input type="hidden" name="url" value="$return_link" />
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<tr>
<td class="thead">$vbphrase[notices]</td>
</tr>
<tr>
<td class="alt1">
$notices
</td>
</tr>
</table>
<br />
</form>
</if>
<if condition="$show['forumdesc']">
<table class="tborder" cellpadding="$stylevar[cellpadding]" cellspacing="$stylevar[cellspacing]" border="0" width="100%" align="center">
<tr>
<td class="alt1" width="100%"><strong>$foruminfo[title]</strong> <span class="smallfont">$foruminfo[description]</span></td>
</tr>
</table>
<br />
</if>
<if condition="$show['popups']">
<!-- NAVBAR POPUP MENUS -->
<if condition="$show['searchbuttons']">
<!-- header quick search form -->
<div class="vbmenu_popup" id="navbar_search_menu" style="display:none;margin-top:3px" align="$stylevar[left]">
<table cellpadding="4" cellspacing="1" border="0">
<tr>
<td class="thead">$vbphrase[search_forums]</td>
</tr>
<tr>
<td class="vbmenu_option" title="nohilite">
<form action="search.php?do=process" method="post">
<input type="hidden" name="do" value="process" />
<input type="hidden" name="quicksearch" value="1" />
<input type="hidden" name="childforums" value="1" />
<input type="hidden" name="exactname" value="1" />
<input type="hidden" name="s" value="$session[sessionhash]" />
<input type="hidden" name="securitytoken" value="$bbuserinfo[securitytoken]" />
<div><input type="text" class="bginput" name="query" size="25" tabindex="1001" /><input type="submit" class="button" value="$vbphrase[go]" tabindex="1004" /></div>
<div style="margin-top:$stylevar[cellpadding]px">
<label for="rb_nb_sp0"><input type="radio" name="showposts" value="0" id="rb_nb_sp0" tabindex="1002" checked="checked" />$vbphrase[show_threads]</label>
<label for="rb_nb_sp1"><input type="radio" name="showposts" value="1" id="rb_nb_sp1" tabindex="1003" />$vbphrase[show_posts]</label>
</div>
</form>
</td>
</tr>
<if condition="$vboptions[threadtagging]">
<tr>
<td class="vbmenu_option"><a href="tags.php$session[sessionurl_q]" rel="nofollow">$vbphrase[tag_search]</a></td>
</tr>
</if>
<tr>
<td class="vbmenu_option"><a href="search.php$session[sessionurl_q]" accesskey="4" rel="nofollow">$vbphrase[advanced_search]</a></td>
</tr>
$template_hook[navbar_search_menu]
</table>
</div>
<!-- / header quick search form -->
</if>
<if condition="$show['member']">
<!-- user cp tools menu -->
<div class="vbmenu_popup" id="usercptools_menu" style="display:none;margin-top:3px" align="$stylevar[left]">
<table cellpadding="4" cellspacing="1" border="0">
<tr><td class="thead">$vbphrase[quick_links]</td></tr>
<if condition="$vboptions['enablesearches']"><tr><td class="vbmenu_option"><a href="search.php?$session[sessionurl]do=getdaily">$vbphrase[todays_posts]</a></td></tr></if>
<tr><td class="vbmenu_option"><a href="forumdisplay.php?$session[sessionurl]do=markread">$vbphrase[mark_forums_read]</a></td></tr>
<tr><td class="vbmenu_option"><a href="#" onclick="window.open('misc.php?$session[sessionurl]do=buddylist&focus=1','buddylist','statusbar=no,me nubar=no,toolbar=no,scrollbars=yes,resizable=yes,w idth=250,height=300'); return false;">$vbphrase[open_contacts]</a></td></tr>
$template_hook[navbar_quick_links_menu_pos1]
$template_hook[navbar_quick_links_menu_pos2]
<tr><td class="thead"><a href="usercp.php$session[sessionurl_q]">$vbphrase[user_control_panel]</a></td></tr>
<if condition="$show['siglink']"><tr><td class="vbmenu_option"><a href="profile.php?$session[sessionurl]do=editsignature">$vbphrase[edit_signature]</a></td></tr></if>
<!--<if condition="$show['avatarlink']"><tr><td class="vbmenu_option"><a href="profile.php?$session[sessionurl]do=editavatar">$vbphrase[edit_avatar]</a></td></tr></if>-->
<tr><td class="vbmenu_option"><a href="profile.php?$session[sessionurl]do=editprofile">$vbphrase[edit_your_details]</a></td></tr>
<tr><td class="vbmenu_option"><a href="profile.php?$session[sessionurl]do=editoptions">$vbphrase[edit_options]</a></td></tr>
$template_hook[navbar_quick_links_menu_pos3]
<tr><td class="thead">$vbphrase[miscellaneous]</td></tr>
<if condition="$show['pmmainlink']"><tr><td class="vbmenu_option"><a href="private.php$session[sessionurl_q]" rel="nofollow">$vbphrase[private_messages]</a></td></tr></if>
<tr><td class="vbmenu_option"><a href="subscription.php$session[sessionurl_q]" rel="nofollow">$vbphrase[subscribed_threads]</a></td></tr>
<tr><td class="vbmenu_option"><a href="member.php?$session[sessionurl]u=$bbuserinfo[userid]">$vbphrase[your_profile]</a></td></tr>
<if condition="$show['wollink']"><tr><td class="vbmenu_option"><a href="online.php$session[sessionurl_q]">$vbphrase[whos_online]</a></td></tr></if>
$template_hook[navbar_quick_links_menu_pos4]
</table>
</div>
<!-- / user cp tools menu -->
</if>
<!-- / NAVBAR POPUP MENUS -->
<!-- PAGENAV POPUP -->
<div class="vbmenu_popup" id="pagenav_menu" style="display:none">
<table cellpadding="4" cellspacing="1" border="0">
<tr>
<td class="thead" nowrap="nowrap">$vbphrase[go_to_page]</td>
</tr>
<tr>
<td class="vbmenu_option" title="nohilite">
<form action="$vboptions[forumhome].php" method="get" onsubmit="return this.gotopage()" id="pagenav_form">
<input type="text" class="bginput" id="pagenav_itxt" style="font-size:11px" size="4" />
<input type="button" class="button" id="pagenav_ibtn" value="$vbphrase[go]" />
</form>
</td>
</tr>
</table>
</div>
<!-- / PAGENAV POPUP -->
</if>
<if condition="$show['member'] AND $notifications_total">
<!-- notifications menu -->
<div class="vbmenu_popup" id="notifications_menu" style="display:none">
<table cellpadding="4" cellspacing="1" border="0">
<tr><td class="thead" colspan="2">$vbphrase[your_notifications]</td></tr>
$notifications_menubits
</table>
</div>
<!-- / notifications menu -->
</if>
$ad_location[ad_navbar_below]
I've removed the Community and Quick Links already, so you don't have to do the edits. :)