Display of add/edit new post is dysfunctioning

Hi !
Since wordpress 4.0 update, the page “post.php” or “post-new.php” seems to have a CSS problem :

https://i39.servimg.com/u/f39/12/31/12/43/post-w10.jpg
https://i39.servimg.com/u/f39/12/31/12/43/post-010.jpg

I’ve no access to visual editor (the link is broken or acting like a # link). The others buttons are ok, but no WYSIWG editor (and a smaaaaaall small input field).

I’ve tried :
– re-update WP 4.0
– rollback to WP 3.9.x
– backup my blog with EasyPhp : no problem on localhost
– re-upload files : wp-admin, includes, etc.
– desactivate all plugins
– use wordpress theme Twenty-eleven, twelve, thirteen, etc.
– use the trick in wp-config :
define( 'CONCATENATE_SCRIPTS', false );
– Firefox, Chrome (never IE)
– different computer (at work)

I prefer not to reinstall completely my blog, since each time it takes me hours of battle with medias (I know how to use add from server & regen images but it’s long and dont work perfectly. With lot of content, it’s a nigthmare.)

So, I wait the 4.1 release, I use Windows Live Writer, but maybe somebody here have a magic trick…?

PS : my english is bad, and I should feel bad, I know ??