Quote Originally Posted by c123

easiest way to solve this is to use K => Settings => SysV-Init Editor. I removed KDM from the list of services that start up when passing to run level 5.

So I used a GUI app, but I *shall* learn to do this from the command line!
I believe the proper syntax is update-rc.d -f kdm remove as root this will leave the script in place if you every want to change it back.