XDM starting when not wanted

[Barbara Pfieffer]

I setup potato on an older Dell laptop. It worked great and I just kept 
updating everything, X windows and so on. It had uptime of 38 days when 
I finally decided to reboot. Somewhere along the way, xdm get set up to 
start on bootup for a graphical login. I do not want this, I want to 
boot to a console login. I don't use X much on the computer and startx 
works fine when I want to go to X. How can I stop XDM from starting on 
bootup?

Thanks
Barbara