Comment 10 for bug 1069133

Q:However, I don't know what the PPA for the 'official' Xorg is - is it within the normal Ubuntu PPAs?

A:You do not need a ppa for the official xorg it is just in precise main.

Q:I've disabled the edgers one and tried to reinstall x but still not having much success.

A:You can try first to install the components from terminal, unfortunally I could not find nvidia specific, I have only ati/amd for know, but the principle components must be similiar(have a internet search please for nvidia):

sudo apt-get install xserver-xorg-video-ati
sudo apt-get install --reinstall libgl1-mesa-glx libgl1-mesa-dri xserver-xorg-core

Remove first the ppa from sources.list (/etc/apt/sources.list),

when you do manually you need

gksu nautilus