If you have just done your initial install.
1. Use phpMyAdmin to drop all the tables in the database. 2. Go into sites/default and delete settings.php 3. Goto www.YourSiteURL.com and run the install again
If there has been nothing done or added to your site, you will not loose anything and save a lot of frustration.
When you start activating modules, the first one should be backup and migrate. After you activate it, do a backup of the database. You will be able to get there by going to: admin/config/system/backup_migrate Then activate your other modules two or three at a time with a backup in between. This way you can figure out which one caused this problem. The backups are so you can go back to before the problem module messed up the DB and you wont have to go through this all over again.
Hope this helps,
Cory