This happened to me recently when I installed some updates via synaptic. I rebooted and it went to low graphics mode because X decided to overwrite (i assume) my conf file that WAS working just fine.
I fixed this problem by manually editing xorg.conf to the following values. I was able to boot into gnome but then I exited to the prompt via alt+cntrl+f3. Section "Device" Identifier "Nvidia Geforce 6600" Driver "nvidia" EndSection -- GeForce 6600 not supported https://bugs.launchpad.net/bugs/313306 You received this bug notification because you are a member of Ubuntu-X, which is subscribed to nvidia-graphics-drivers-180 in ubuntu. _______________________________________________ Mailing list: https://launchpad.net/~ubuntu-x-swat Post to : ubuntu-x-swat@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-x-swat More help : https://help.launchpad.net/ListHelp