I just installed ubuntu 12.04 on a asus a55v, in dual boot with windows 8. I added Bumblebee for the use of the nvidia 601m graphic card. Because I had problems with 3d effects, and the problem seems to be in the GLX library in Xorg, I gave
sudo apt-get install --reinstall libgl1-mesa-glx xserver-xorg-core
and then shutdown the pc (but I did also a lot if other stuff before, so I'm not sure that this last problem is related to the story).
When I switch the laptop on again, the disaster: when I arrive to the loading screen, suddenly a black screen appears, and nothing else happens any more.
How can I at least know where is the origin of the problem?
EDIT: I repeated all the operations again, and now I see that the problem starts after the installation of CUDA. Note that I didn't install the nvidia graphic card drivers, but only the toolkit and the samples. So it seems very strange to me, and I have no idea on what it's happening.