Problems moving wordpress to the root domain

When I installed WordPress I put it at example.com/wordpress. After several weeks of accessing it there, I decided to integrate WordPress into the root of my domain. So I removed all the html files I had made on my own, then copy and pasted all the files in the WordPress folder into the root. This did not work at all. So I decided to put everything back the way it was. Except now when I go to example.com/wordpress I get a 404 Not Found message. Assuming I actually did put everything back the way it was originally, why would this be happening? And what is the correct way of moving WordPress to the root domain?