after restoring a host backup

i recently had a problem with my host. my public_html was deleted and i needed to restore a backup of it. the backup was restored and all the files were back on the public html.

when i go to my wordpress website: http://www.spirrsblog.com i get the following message:

Warning: require(/home/spirrsbl/public_html/wp-includes/compat.php) [function.require]: failed to open stream: No such file or directory in /home/spirrsbl/public_html/wp-settings.php on line 246

Fatal error: require() [function.require]: Failed opening required ‘/home/spirrsbl/public_html/wp-includes/compat.php’ (include_path=’.:/usr/lib/php:/usr/local/lib/php’) in /home/spirrsbl/public_html/wp-settings.php on line 246

Can someone tell me what i need to do inorder to get my website back???

thanks you so much, this is so urgent.
-Lex