I suppose u r in a live-cd and u dont get GUI.
I suppose ur graphics card also is nvidia make.nvidia gfx cards needs drivers either open source "nv" or proprietory "nvidia".so when the garbled colour screen appears,just press keyboard keys CTRL+ALT+F1 to get a vte.if there is "#" prompt already there,we can proceed.else
oh,now u need a username to login.hmm..for that login as ubuntu and passwd may be ubuntu too.I'll check and post here soon.
Now to the problem,
U need to edit the /etc/X11/xorg.conf to set driver as "vesa"
the editor used is "nano" it is easy to use.go to section "Device" and edit the
save by pressing CTRL+O(letter) and exit by CTRL+X.now in the terminal type
Code:
~#/etc/init.d/gdm restart
^in linux and unix space must be respected