In this short tutorial, I will show you how to stop a program from running at startup on Debian based distros, such as: Ubuntu, Linux Mint, Knoppix and Redhat based distros such as Fedora, CentOS, Mandrake or OpenSUSE.
I will use apache2 as an example. Replace it with the service you want to prevent from running at System startup.
Disable programs from running at startup on Debian and friends: sudo update-rc.d -f service_name remove
$ sudo update-rc.d -f apache2 remove
Disable programs from running at startup on RedHat and friends: sudo chkconfig service_name off
$ sudo chkconfig apache2 off
To see which applications are running, use ps or top after you boot your computer.