how to stop nxfree or freenx-server on boot up

I'm not really familiar with NX. Try doing a chkconfig –list and see if you find those in that list. If you do, try the command chkconfig off. After that, perform the first command again and see that the whole row says "Off".

> Try doing a chkconfig –list and see if you find those in that list. This assumes that he/she's using a RH-like distro. For anything Debian based, you can also update your init script directories with something like update-rc.d -f freenx remove. Man update-rc.d first.