The Apache Server, is a web server that comes with every Linux distribution and of course with Ubuntu. Also in most cases Apache is automatically setup during installation procedure. And after that it starts automatically on boot time or reboot of Ubuntu. In some cases you may need to disable it. The easiest way to that is to use tool called Rcconf. Rcconf configures system services whatever to start or not during boot time. It turns on/off services using the scripts in /etc/init.d/. It is a frontend to the update-rc.d command.
In most Debain based distros such as Ubuntu Rcconf comes pre-installed. So first make sure it is installed by running the following command:
sudo apt-get install rcconf
Once the above command is run, your will have rcconf installed on your Ubuntu system.
Now type the following command on you terminal window:
And you will see list of services that are installed on your Ubuntu machine. Those marked with star are auto run during boot process. To disable Apache or any other service such as MySql just navigate to it using arrows and press space bar. Then navigate to OK button using Tab key and again press Space to save configuration.