lenmcgrane

I have messed up badly, trying to follow this advice. Can you help dig me out?

I have started to build
http://www.how-to-hypnotize-anyone.com
and have made two pages private. They are:
domain/confirm
domain/collect

I tried to get rid of the
Private:
that appears in the headline of the two private pages by simply changing the word ‘Private:’ to ‘123’ in the post-format.php file in wp-includes. (Just a test.)

That is, I changed
$title = sprintf(__('Private: %s'), $title);
to
$title = sprintf(__('123: %s'), $title);

When I went to the two private pages I got a 404 error message both times. I reverted to the orig line of code. Still 404. I changed the permissions on the file post-template.php to 644 and then to 777 (temporarily) and still got 404.

Then I uploaded another copy to the post-format.php file from WordPress.org. Still getting the 404.

Can you show me how to change the word ‘Private’ without incurring the 404?

Or do I have to uninstall my WP site and start again? (That would not be too hard. There is not much content on the site yet.)

Thanks,
Len