Remove - Subscribe to: Posts (Atom)

1. Go to dashboard/ template/ edit HTML
2. Click the 'Expand Widgets Templates' box
3. Find:

<b:if cond='data:blog.pageType != "item"'> <!-- Blog feed links -->
<b:if cond='data:feedLinks'>
<div class='blog-feeds'>
<b:include data='feedLinks' name='feedLinksBody'/>
</div>
</b:if>

Remove this line:

<b:include data='feedLinks' name='feedLinksBody'/>

That should remove Posts (Atom).