Go to the dashboard, change registration mode to invitation, then go to roles and permissions and remove invitation permission from all non-admin users. Voila!
the idea was to show a message registrations disabled or something like this
This may be a cheap way out, but you can create a new theme (if you aren't using your own already), and override the appropriate registration view. If you've set it up like @TiGR said (invitation only), you can copy: /applications/dashboard/views/entry/registerinvitation.php to your /themes/yourtheme/views/entry/registerinvitation.php and then just remove the form markup and put a custom message there instead.
There is a feature called Messages. You can post messages on all, or only some, pages. Go to your dashboard, look under Appearance, and choose Messages.
Comments
the idea was to show a message registrations disabled or something like this
/applications/dashboard/views/entry/registerinvitation.php
to your
/themes/yourtheme/views/entry/registerinvitation.php
and then just remove the form markup and put a custom message there instead.
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