“Error connecting to database” (can’t finish install)

Hi all. I see there is a lot of this question on the boards, so my apologies for sounding repetitive. However, none of the proposed solutions seem to fit my situation (key word, “seem”).

I have been trying to upgrade my version from 2.6 to 2.8.3, though I’ve not been able to bring up the wp-admin page, only getting this error:
———

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 localhost. 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.

———————–

• My username and password are correct in wp-config.php.
• Thinking some files may have been corrupt during the upgrade, I decided to do a fresh install (I don’t care much about my site, just the data); THAT didn’t work (I deleted all files from the directory, then uploaded the latest version files with the wp-config.php updated with UN and PW)
• When THAT didn’t work, I created a brand new DB to see if maybe it was my DB. So I set up a new directory, loaded the freshly extracted WP 2.8.3 files into it, ensured I put in the right info in the

wp-config.php…

Same result.

So, now I’m completely stuck. Mysql version = 5.0, btw.

Ideas?