Problems with the database

I’ve installed wordpress on my home server.
I use IIS 5.0
I have PHP 4.4.2 installed and working fine
I have MySQL Server 5.0
I use SQLYog as a frontend
I’ve created a wordpress database
I’ve updated wp-config to reflect the following

define(‘DB_NAME’, ‘wordpress’); // The name of the database
define(‘DB_USER’, ‘root’); // Your MySQL username
define(‘DB_PASSWORD’, ‘mypassword’); // …and password
define(‘DB_HOST’, ‘localhost’); // 99% chance you won’t need to change this value

I deleted the database and recreated it from the MySQL CLI as per the steps in the Codex.

But I still get the error
Error establishing a database connection

I’ve looked through the other topics in the forums for this error but couldn’t find any resolution to mine.