Login Trouble – Error 404

I recently installed WordPress for my domain which is hosted at godaddy.com. I think I must have changed an address somewhere because now when I go to http://www.littleblueplaques.co.uk/wordpress/wp-admin it comes up with an Error 404. I’ve tried every domain can think of to get to the admin page but it always comes up with the error message.

Any help would be much appreciated. Also, while I’m here, how do I change it so the admin login page is at http://www.littleblueplaques.co.uk/wp-admin?