I updated my laptop to unity (ubuntu 11.10), still with Lightnings though:-
After updating to proprietary drivers (big mistake) it took 2 days to figure out how to get back any graphics at all. Text login was not fun for the first 1 1/2 days, then sadly I started to like it.
So if anyone else has a Lenovo Z570 with Nvidia Cuda Geforce GT520M – leave it alone for the moment.
Here is the code I used to restore:-
sudo apt-get purge nvidia*
sudo rm /etc/X11/xorg.conf
sudo apt-get install –reinstall xserver-xorg-core libgl1-mesa-glx libgl1-mesa-dri
sudo dpkg-reconfigure xserver-xorg
This is mainly for me in case I try it again, but maybe will help someone else.