attempted uninstall reinstall failed :-(

I just started using wordpress. My first installation went very smoothly. Unfortunately after playing with a couple of themes and plugins I noticed that my ability to assign a parent page was gone. Checked for support and tried to disable the plugins with no luck. Next piece of advice was to do a fresh installation of wordpress. I proceeded to delete all the files and folders on the server and then deleted the database. Created a new database and put a fresh batch of files on the server (with the updated config.php for the new database) but I get the error “Error establishing a database connection”. I just can’t figure out what I am doing wrong since I am following the steps of my first installation. Any advice?