Error message

Hello everybody,

I’ve got a WP website for my business and this morning got this message:

Warning: require(/home/u235085140/public_html/wp-includes/version.php) [function.require]: failed to open stream: No such file or directory in /home/u235085140/public_html/wp-settings.php on line 30

Fatal error: require() [function.require]: Failed opening required '/home/u235085140/public_html/wp-includes/version.php' (include_path='.:/opt/php-5.2/pear') in /home/u235085140/public_html/wp-settings.php on line 30

I have no idea what is it about. The last time I made some changes was last Monday, when I pusblished a new post on the blog. Also, on Tuesday I realize ‘somebody’ had posted spam on the blog and deleted it. But I haven’t upgraded anything else (at least conciously as I am a photographer and have not a clue about this).

On the other hand, I have no access to the web through WP-admin… I am desperate, anybody knows what has happened and how could it be solved?

Thank you so much.