preventing gnome from starting

Thu Aug 6 10:24:07 UTC 2015

-- 
Kristoffer Gustafsson
Salängsgatan 7a
tel:033-12 60 93
mobil: 0730-500934
Hi.
Ok, finally I have begun to install debian on one of my computers.
But I don't dare to install gnome yet, since it became very bad the
last time with the screen thing.
But sooner or later I will have to use gnome.
So my question is this. How do I prevent gnome from starting if this
thing goes wrong.
I don't want to be unable to use my Linux machine if I don't have a screen.
/Kristoffer