After updating: error at wp-settings.php on line 206

I was trying to update. Instead of deleting all folders and files, I only delete it the files in the root directory and overwrote the other folders, with the exception of plug-ins.

I did update config.php with the correct information which was on the original config.php I backed up. The error I got after running /wp-admin/upgrade.php is:

Fatal error: Call to undefined function: require_wp_db() in /hsphere/local/home/philesq/philsbest.com/wp-settings.php on line 206

Thanks.