ReInstall trouble after site was hacked

Hello,I’m new to WordPress and have only created a few basic sites. One of my wordpress sites has been hacked as it was in the construction stage. Now I’m locked out of the dashboard. I can’t reset the password via email or phpadmin panel I even tried the emergency.php script and can’t get in.
I decided to ditch all the files on the server and start again with a new database with the aim to rebuild the site.
Does anyone know if you can reinstall wordpress if you were already installed with the same web address?
I’ve tried the install with the new database and I get the message “Can’t Select Database. We were able to connect to the database server (which means your username and password is okay) but not able to select the database”
I have check it exists and that the user is added to it.
Is this just my database setup error or is it because I once had a site already installed?
Thanks.