Error establishing a database connection

You need to provide a lot more info than that. Which version of yahoo hosting? What exact error display are you getting? What are your wp-config.php settings (xxx out the u/name and pw for safety)?

Where do I get this info? “What are your wp-config.php settings (xxx out the u/name and pw for safety)?”

I have Web Hosting Starter. It works sometimes, sometimes going to this page: I just checked. After a few minutes when I click something in WP this happens.

Error establishing a database connection
This either means that the username and password information in your wp-config.php file is incorrect or we can’t contact the database server at mysql. This could mean your host’s database server is down.

Are you sure you have the correct username and password?
Are you sure that you have typed the correct hostname?
Are you sure that the database server is running?
If you’re unsure what these terms mean you should probably contact your host. If you still need help you can always visit the WordPress Support Forums.

Did you upload the wp-config.php file as per the docs? Did you make sure that the username, the password etc. are what your host gave you for the database you created?

Well I downloaded everything from Yahoo!.
Set up a user name password at that time.
The username password were working fine this AM.

Okay, so you had connected to the blog at one point? And THEN later you got the error? Had you done anything with the blog in between?

If that’s the situation, and you hadn’t done anything, then you need to talk to yahoo to see if they did something to the backend programs that run on the server.