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

Question

Update: Already fixed, it seems that one of VirtualHosts configurations files was wrong in sites-enabled.

I have Ubuntu 11.10

When I run the command to start

Answer 1

use either

sudo killall httpd

or

sudo killall apache2

check if some one using the 80 port

sudo netstat -tulpn| grep :80

The restart

sudo service httpd start

then restart the server.It took me a whole day to understand the issue