How do I "kill off" that additional fourth page and the ubiquitous "error 404 notation"?

I can't seem to be able to kill off that added fourth page (which I thought, with my GYBO account I'd have up to five free pages.)? Not that I'm complaining about having to forego the extra page. But everytime I go to publish the three first pages, I get this reminder I've exceeded my three pages and they'd only be published. That's okay, but how do I get rid of that last added extra page I don't want anymore, esp. off my title head section that tells any visitor what's available ... when it's not? Also ... has anybody found a way to zap "error 404"? I've seen it for years and never found a way to wipe that clean as well?