Creating a registration

Hi, I just started putting up my first WP site, and I’m running into a couple problems that are a little too complicated for me. I understand that there are plugins for registration, but what I’d like to do with the login/registration page is make it the only page accessible on my site until the user has registered. After registration, the site should be fully accessible. Are there any good plug ins that can do this, or do I have to do code?