Hello - I am receiving the same error - Error establishing a database connection - my blog is:
I've gone through 8 hours of reading threads about correcting a partial upgrade, manually installing a blog, checking wp-config.php, learned how to deactivate plugins when I can't log in ... I've tried everything I can find.
I deactivated the theme manually as well - at least my page is up but if you click on anything it says - Error establishing a database connection
I can't get to login.
I am using yahoo hosting ...