Anyway it is quite simple as just deleting all the files and folders related to your Wordpress blog and remove the database. By default you will see three folders and file names start with "wp_" with index.html, license.txt, readme.html and xmlrpc.php.
If you are using a web server management tool it will provide a user friendly interface to delete the database from the server. Other wise you can use my sql command to do so.
Drop [Database name]
If you are using the command line option or interface always double check whether you are deleting the correct database. I recommend to take a backup of every database you have before you execute such commands.
Here is a useful video demonstration How to Install WordPress 2.7, 2.8, or 2.9 through Cpanel.
This will totally uninstall the Wordpress blog from your server and you can install a fresh copy of Wordpress now.