Displaying “old” database data after upgrading WP…

I’ve had wordpress issues during the past two weeks after my ftp client started deleting all my files instead of a single file in a very bad one time glitch. I’ve since tried reinstalling/upgrading wordpress and now seem to have a functional version 2.6 running but I can’t see any of my old data via blogs and such, though it’s in the database still. Does anyone know how to “connect” wordpress to the database? I thought it did that when I created the wp-config.php file.

I’ve also exported an SQL file so if there’s a way to import that into wordpress it’d help me as well. And I have some files in the WP-content directory which wouldn’t delete when I removed the other WP files.

I’ve tried searching for this answer but keep getting linked to connecting wordpress to an unpopulated database to start from scratch.

Thanks.