You successfully disabled comments on Posts. Now you need to disable them on Pages.
This page > Settings > Discussion
Discussion settings is where you set up defaults for comments.
http://en.support.wordpress.com/settings/discussion-settings/
We can also override the default settings and enable or disable future comments on any individual post or page.
http://en.support.wordpress.com/enable-disable-comments/
Note 1: By default, new blogs on WordPress.com will have the Discussion hidden. You can reveal it by clicking on Screen Options http://en.support.wordpress.com/screen-options/ on the top right corner of your Admin page, and checking the box that says Discussion so the module is included. http://en.support.wordpress.com/modules/#list-of-modules
Pages - Bulk Closure
Go to Pages > All Pages, click the little square to select all the pages, select "Edit" from the Bulk Actions pulldown, click Apply, select "Do not allow" from the Comments pulldown, click Update. From: http://en.forums.wordpress.com/topic/how-can-i-omit-the-leave-a-reply-box-from-my-pages?replies=4#post-1067546