I had a working 12.04 install on my laptop with bumblebee and the old nvidia-current drivers until last night when I tried to install the new 310.19 Nvidia drivers. I fought back and forth, at first only able to boot into a 640x480 resolution. I tried a few different options installing different driver versions. I eventually had to resort to the xorg.conf.failsafe config to have a working pc again. I still cannot get unity to run in anything but 2D mode, and I can no longer use optirun.