If Fantastico was used to install Joomla then it can also be used to remove Joomla.
Do you have a backup? Download backups (files and database) from cPanel before using Fantastico if there is any chance you may want to revert to your present state.
Then make sure that no files or folders have permissions higher than 755 or removal will fail. Unless someone changed the permissions they should be this way already.
In Fantastico (blue "smiley face" icon at bottom of cPanel) click the Joomla 1.5 link on the left ( or Joomla for 1.0 ).
This will display the existing Joomla installations that Fantastico installed. Look for the "remove" link beside each installation. Clicking "remove" will delete the Joomal files and database in one step. There is no undo.
Fantastico Facts:
Fantastico keeps a record of the files to delete in a file called fantastico_fileslist.txt.
Joomla versions are recorded in the file called fantversion.php which is required for Fantastico upgrades.
There is also an invisible folder in your home directory called .fantasticodata that keeps track of installation information.
By studying the files in these folders it is possible to "trick" Fantastico into thinking it installed Joomla even if it didn't (manual install, Rocket installer, etc.) by creating theses files and entering the proper information.
