Deformed back end

Did you edit the functions.php? Your js/css could be clashing with the admin css or js.

If you are using Internet Explorer, press F12 and double check if the ‘browser mode” and “document mode” are set to the latest installed browser version.

Site url?

The only way was to reinstall wordpress. do what.

Well, I guess that means you came right eventually? Then mark this as resolved.