This is pretty common when your .htaccess file is messed up.
Try to restore it by pasting these contents: http://codex.wordpress.org/htaccess
Between # BEGIN WordPress and # END WordPress
Type: Posts; User: Gianluca
This is pretty common when your .htaccess file is messed up.
Try to restore it by pasting these contents: http://codex.wordpress.org/htaccess
Between # BEGIN WordPress and # END WordPress