How did you setup your joomla database cusa86? Do you have phpMyAdmin on your webhosts control panel? If your mySQL database was setup through your host you should be able to select it and locate any fireboard tables and drop them.

I'll clear this up because I've encountered this issue.
I installed the first release of Fireboard right as it came out and chose to upgrade from JoomlaBoard. I then uninstalled it. Then when a more stable release came out, I chose to install that but no longer received the option to upgrade from Joomlaboard.

My Joomla database is named: _joom4

I opened up phpMyAdmin and selected _joom4 from my list of databases. Insisde this database there are tables labeled `jos_fb_sessions` and similar. I selected all of the tables starting with jos_fb and chose to "Drop" them. If you are using a command prompt or other mySQL client, use the command DROP TABLE `jos_fb_sessions` to drop the tables related to fireboard.

Then upload the latest fireboard component. Once installed, go to components>Fireboard. At the top of the Fireboard control panel you will see the options of Clean Installation and Upgrade from Joomlaboard once again, Click apply under Upgrade from Joomlaboard.