Okay. This isn't referring to a FRESH Install but rather a CLEAN install where you would need to wipe the slate (database) clean of your previous FB install and reinstall it. This is taken straight from the manual included in the FB download (with a little editing).

Uninstalling Fireboard

Important Note
By Uninstalling all your Fireboard files will be deleted! However, if you have a version greater than 1.0.2, your uploaded files, avatars and all the files that are under “Joomla_Root/images” directory will not be deleted. Also, your database tables will not be dropped.

1. Go to Administrator > Installers > Components
2. Select Fireboard and click Uninstall.
3. After this point, you can decide if you want to completely uninstall Fireboard or leave the database tables and uploaded files intact.
3.1. If you want to completely Uninstall fireboard:
Apply the following database queries:

[code:1]DROP TABLE `jos_fb_announcement` ,
`jos_fb_attachments` , `jos_fb_categories` , `jos_fb_favorites` , `jos_fb_groups` , `jos_fb_messages` , `jos_fb_messages_text` , `jos_fb_moderation` , `jos_fb_ranks` , `jos_fb_sessions` , `jos_fb_smileys` , `jos_fb_subscriptions` , `jos_fb_users` , `jos_fb_whoisonline`[/code:1]

(If you don’t know how to access/use phpmyadmin, please read: http://community.mybboard.net/showthread.php?tid=4720)

[b]FAILURE TO EXECUTE STEP 3.1 WILL RESULT IN foreach() (and possibly other) ERRORS!! You have been warned.[/b]

4. Delete “Joomla_Root/images/fbfiles/” directory.

[b]Installation/Reinstallation[/b]

1. First, unpack the archive on your local computer.
2. Go to your Joomla! Administration > Installer > Components
3. Click Browse, Select the package (zip) and click on “Install”.
4. After a successful installation, go to Components > Fireboard Forum
5. Once you enter the control panel, at top of the page you will notice a dialog asking you whether you want to upgrade from “Joomlaboard” or a “Clean Install”. If you click on Clean Install you will have a fresh installation of Fireboard and necessary database tables are generated automatically.
6. [Optional] You can also try your new board by “loading sample data” which creates a dummy category and a post. We recommend this option to get familiar with creation of categories and post administration.

However while step 6 is recommended in the manual I do not. It seems to cause more problems than it solves. I personally have never installed the sample data and have had no problems whatsoever.