Linux startup service scripts are found in the directory /etc/rc.d/rc#.d/ (for Rehdat) where the symbol # represents the run level.
i.e. the run level "3" will run all the scripts in the directory /etc/rc.d/rc3.d/ which start with the letter "S" during system boot. This starts the background processes required by the system. Services start in numerical order. S20abc is run before S30xyz. These
S# and
K# files are just links to the actual scripts in /etc/init.d
Note: K is for kill or shutdown. Those scripts are executed when you shutdown the system.
If you are in runlevel 5, then have a look at /etc/rc.d/rc5.d and see how the scripts have been numbered. You can change the numbering, but that should only done if you know what you are doing! Otherwise some services may not start as they are dependent on other.
-Nitin