Error 404 on wp-includes directory

Question

I'm having a lot of 404 errors for files which are supposed to be in the /wp-includes/ folder.

This makes some part of the website and the admin panel unusable (in the edit post page it won't even load tinymce editor).

I have the latest version of wordpress 4.1 and some plugins that I'm already using on other websites.

I've tried to disable theme and plugins, reupload wp-admin and wp-include via ftp but nothing changes. Also uploaded a clean .htaccess, and nothing. Same by reverting to an older version of wordpress. Any idea about what can be a solution? Looking in the ftp, the folder is there, and file permissions are set properly(755 folder, 644 files). But everything in it is unreachable from the broser.

The website is: http://www.queylus.com/ you can see that it fails to load jquery library (i've included it manually in the header as a temporary solution to make the website work)

Answer 1

I've found what was the problem. An old version of Slider Revolution plugin, that probably was hacked.

I upgraded the plugin to the latest version and now everything is fine.