Salutation: WordPress + BuddyPress Theme

First, make sure you have BuddyPress installed. The theme does not require BP, however the registration page is a BP feature.

Second, make sure registration is enabled for your site:

For single WP install, go to “Settings > General” and check “Anyone can register”.

For a multisite install, go to “Super Admin > Options” and select the option you want under “‘Allow new registrations”.

Globally disabling comments on new pages and posts:

Go to “Settings > Discussion” and deselect the option “Allow people to post comments on new articles”. This applies to both pages and posts.

Single page/post disable comments:

To individually disable comments on a page or post, from the edit screen click the tab at the top right “Screen Options” and check “Discussion”. This adds a box to the edit screen where you can deselect the options for comments and trackbacks.