How do I regain the ability to create databases (phpMyAdmin)?

I've finally got both PHP and MySQL up and running, and I've learned how to create new users and databases (at least the basics). But I was told I should add a password to root/localhost, and that's been a major pain in the butt. First, it knocked out phpMyAdmin. Then I learned how to edit a file (phpMyAdmin.config.inc, or something like that), which restored phpMyAdmin. But I next discovered that I can no longer create databases. When I open up phpMyAdmin, near the top of the page is a function for creating new databases. It now says "No Privilieges," just under "Create New Database." I tried to retrace my steps in creating a password. I clicked on Privileges, then clicked Edit in the root/localhost row. Then I went down to where it says "Change Password," clicked the Password radio button and typed in my password twice. I don't think I did anything else. So why would that knock out my databases? More important, how do I get them back? Thanks.