[CentOS] Bullet proof cron job???

I have a cron job that runs once a day. There are times when it runs that it disrupts other things on the computer, so I want to kill it. Under Mandriva I had no problems killing the process, and that was the end of that. Under Centos I cannot kill it with a sig 15 or a sig 9. Tonight the process would have trashed hours of work, so after spending two minutes as root trying to kill the process, I ended up killing the entire tree, including crond. Linux is supposed to allow CONTROL of things like this without rebooting, etc, so why can't I kill the process without killing crond?

Ted Miller