Why doesn’t unchecking “Anyone can register” work?

“Anyone can register” is NOT checked, but I get 50 spam registrations per day – Why? How?

I don’t have any kind of membership plugin. I do have a small shopping cart plugin, but even when I disable that plugin I still get spam registrations.

How can I stop people from registering? I have tried 3 plugins and they haven’t stopped fake registrations. Where are these bots going to register for my site? And how do I stop it? Please!

Thank you.