Drupal already installed

The following error must be resolved before you can continue the installation process:

Failed to create a test table on your MySQL database server with the command CREATE TABLE drupal_install_test (id int NULL). MySQL reports the following message: Table 'drupal_install_test' already exists.
  • Are you sure the configured username has the necessary MySQL permissions to create tables in the database?
For more help, see the Installation and upgrading handbook. If you are unsure what these terms mean you should probably contact your hosting provider.
  • To start over, you must empty your existing database.
  • To install to a different database, edit the appropriate settings.php file in the sites folder.
  • To upgrade an existing installation, proceed to the update script.
  • View your existing site.

Please check the error messages and try again.