How do I disable "Create New Account?"

It's in Administer » User management >> User settings. Click the radio button that says: Only siteA logically grouped set of content - also web site. administrators can create new user accounts.

How do I disable User Log In entirely, and how would I get in if I do?

First, you can go to Administer » Site building >> Blocks and change the "Region" setting for the "User Login" block to <none>. Now your user login block will disappear.

In order for you to login, I offer two techniques:

• Enter http://www.myexample.com/user (or, if you don't use Clean URLs, http://www.myexample.com/?q=user). Yes, it is the word "user" -- not your user ID.
• Go to your SiteA logically grouped set of content - also web site. information settings and stick a "login" linkThe technique which points to another page, anywhere on the Internet, from the current page. in the footer. <a href="/user">login</a> I do this on several sites.