I was getting the following error on one my servers, after updating apache2 and php5

 Starting web server (apache2)...(98)Address already in use: make_sock: could not bind to address [::]:80
(98)Address already in use: make_sock: could not bind to address 0.0.0.0:80
no listening sockets available, shutting down
Unable to open logs
failed!

This is what I did to fix the problem

netstat -lnp | grep '80'#output
tcp6       0      0 :::80                   :::*                    LISTEN     18712/apache2

In my case the output showed that apache2 was already using the port, although no sites was working and it was not even possible to stop the apache2 daemon. I ran the following to learn more

ps 18712
PID TTY      STAT   TIME COMMAND
18712 ?        Ss     0:00 /usr/sbin/apache2 -k start

I killed the apache2 process, which was blocking everything

kill 19712

and restarted apache

/etc/init.d/apache start

and everything was working fine again. Hopefully this is useful for someone..