There are times when you need to move WordPress around within your server, and times when you need to move WordPress from one server to another. You don't need to reinstall. WordPress is flexible enough to handle all of these situations.

Easy answer for most installations:

• If database and URL remains the same, you can move by just copying your files and database.
• If database name or user changes, edit wp-config.php to have the correct values.
• If you want to test before you switch, you must temporarily change siteurl and home in the database table wp_options (through phpMyAdmin or similar).
• If you had any kind of rewrites (permalinks) setup you must disable .htaccess and reconfigure permalinks when it goes live.