- select the database need backup in phpMyAdmin
- select the tab of Export, and save as file in a sql format.
- upload the drupal installation files into the proper directory.
- copy the old director of /site/all, in which are the modules and themes to the new site directory. Otherwise some functionalities will miss.
- create the database you want in phpMyAdmin with proper database name.
- select the new database and Import.
- Install the new drupal site.