When Open Registration is set to No, you should not see the Register link (s2Member removes it).
Also, attempting to access the Registration page should result in a message that says "User registration is currently not allowed".
- Screen shot 2012-01-09 at 23.01.20 .png (64.11 KiB) Viewed 143 times
If that's not what you're seeing, I recommend disabling all your plugins except s2Member to see if there's a conflicting plugin that is causing issues.
Also, if you've used an
s2-hacks.php file to make any modifications to s2Member, please post those here so we can look at them.
Finally, I suggest deactivating s2Member and then reactivating it. Be sure to enable Deactivation Safeguards before doing this so that all your current settings are saved (
WP Admin -> s2Member -> General Options -> Deactivation Safeguards).