programs keeps adding itself to the startup on launching

Their are few programs that keep adding themselves to the
start up on launching them. They are quick time player
and real player. They add their auto update and messaging
to the start up. I removed their folders from the
msconfing registery and removed them startup on
HMLK/software/microsoft/windows/currentversion/run
but obviously their is a command that adds the startup
registry key when I run these programs. Does anyone know
how to find this command or registry key and delete it?