I followed the instructions below to the T and it worked very well except that now I have a duplicate copy of my wordpress site both on the sub domain and on the root domain. How do I remove the site from the sub domain? Thanks!!
You can actually just leave your files in that subfolder and follow these steps per the codex.
In the general settings, change your Site Address (URL), not the Wordpress Address URL, to http://example.com/ and save.
Copy (NOT MOVE!) the index.php and .htaccess files from your subdirectory into the root directory of your site.
Open your root directory's index.php file in a text editor
Change the line that says: require('./wp-blog-header.php'); to the following, using your directory name for the WordPress core files: require('./test/wp-blog-header.php');
Login to the new location. It might now be http://example.com/wordpress/wp-admin/ If you have set up Permalinks, go to the Permalinks panel and update your Permalink structure. WordPress will automatically update your .htaccess file if it has the appropriate file permissions. If WordPress can't write to your .htaccess file, it will display the new rewrite rules to you, which you should manually copy into your .htaccess file (in the same directory as the main index.php file.)