Under Debian Linux startup files are stored in /etc/init.d/ directory.
Debian uses scripts to start services at boot time from /etc/init.d/ directory.
I will show two ways with which you can remove unwanted startup files or services:
Firts is rcconf :
Rcconf gets a list of services from /etc/init.d and looks in the /etc/rc?.d directories to determine whether each service is on or off.
apt-get install rccconf