Silly Question: Removing a 404 Redirect page

Right, I’m having a huge problem with spammers, who are targetting my /wp-comments.php page directly and causing my server to overload, despite Akismet, Bad Behaviour and 301’ing direct requests. http://wordpress.org/support/topic/142377?replies=2 for more information.

At the moment, if you go to my blog URL and any random page (http://www.gospelrhys.co.uk/this_page_is_dead.html), you’ll get redirected back to the home page, I’d like it to instead just show up a 404 error, completely unstyled, no redirect, nothing, to save server load.

How do I do this? 🙂