Starting apache fails (could not bind to address 0.0.0.0:80)

When I run the command to start apache2:

sudo /etc/init.d/apache2 start

I run this command in order to get the process that is using the port 80:

sudo netstat -ltnp | grep ':80'

To know which process is I run this command:

ps -wlp1176

But if I try to kill the process:

sudo kill -9 1176