Carry out the following steps:
Open
elements/header.php
from your theme in your text editor.Look for the following highlighted lines and remove all of them:
<div id="wrapper"> <div id="page"> <div id="header_line_top"></div> <div id="header"> <?php $a = new GlobalArea('Header Nav'); $a->display($c); ?> </div>
Next, insert the following PHP code instead:
<?php $autonav = BlockType::getByHandle('autonav'); $autonav->controller->orderBy = 'display_asc'; $autonav->controller->displayPages = 'top'; $autonav->render('templates/header_menu'); ?>
Save the file and reload your page, the header navigation is still there, but if you switch into edit mode, there's nothing you can edit in the header navigation.