When I Make A New Post The Category is Unchecked & Then it Automatically Uses it

I’m using WordPress version 3.3, when I’m about to make a new post the category “nightclubs” is not checked and when I go to publish the post it automatically uses that category by default. I deleted all of the test categories I made & all the post thinking this might reset everything and then went back to delete all the categories again but still I can’t delete that category “nightclubs”. I made the decision that I don’t want any more categories. Some help here would be really great. Here is the link to the blog page where you can see the Posted in Nightclubs showing up on my two post.