WordPress user accounts

Hello.

I’m new to WordPress, so if there’s a functionality i’ve grossly overlooked, please point me to it, and i’ll shut up, in the meantime…

I’m trying to set up a blog where everybody can make a user account, and where you actually NEED a user account to post comments on the blogs posted.

This, as far as i’ve been able to tell in half an hour of browsing through the basic installation and a quick glance at the plugins, is not the standard case.

Right now everybody that happens to stumble upon the site can post comments to the blogs, but i want people to be able to have an account, automatically get signed it to it if they wish, and place comments on posted logs, where your every day random surfer can not.

If there’s a plugin that can do this all for me, please point me to it with a huge sign saying it’s right there, cause i’ve been unable to find it.

I’m no hero with scripting either, so i hope there’s a simple solution for this.

regards,
-Lans