Then do
$ apt-get install xorg xinit
$ xinit
If it's a live CD, HDD space is not used, only RAM; No permanent change to
the computer.
But are you sure you got the right ISO?
There's really no X11 when you boot, 'Try Trisquel without installing'.
I think that you may have confused 'NetInstall' with Trisquel-Mini. Because
the Trisquel-Mini ISO should contain X11, physically. It even includes a
desktop environment and a display manager.
If you're on the Trisquel-Mini LiveCD then
$ ls /usr/bin | grep openbox
should output i believe, as it comes pre-installed.
