Can’t select database…

I installed wamp and all services are running. I installed WordPress and it installed successfully. I created a database named cocn_wp with user root and password blank. When I enter the data and click “submit” I get the can’t select error. I have deleted the database and re-created it. Still get an error. I tried editing the wp-config-sample.php file and saving it as wp-config.php but then WordPress says that wp-config.php already exists even though it says previously not to worry, I can edit & save etc. Clearly this is not working. Any help will be appreciated. Thanks.