I\'m running Ubuntu. My Apache2 default file looks like this:
ServerAdmin webmaster@localhost DocumentRoot /var/www
Have a look in /etc/apache2/sites-enabled. It seems like my upgrade to 10.10 has wiped the symlinks from that directory. Try symlinking default to /etc/apache2/sites-available/default
sudo ln -s /etc/apache2/sites-available/default /etc/apache2/sites-enabled/default