I also solved my problems with today's ISO (http://cdimage.ubuntu.com/daily-live/20120929/quantal-desktop-amd64.iso), I can boot correctly with a live USB key on my PC with an Nvidia graphic card.
I also solved my problems with today's ISO (http:// cdimage. ubuntu. com/daily- live/20120929/ quantal- desktop- amd64.iso), I can boot correctly with a live USB key on my PC with an Nvidia graphic card.