Updated Nvidia graphics driver, now won't make it past the boot screen

Solution 1:

On 12.04 Latest - tested, steps should basically apply for previous.
If it doesn't work, add the output from fdisk -l and mount from recovery console in your question and I'll edit my answer to address it.

Boot to recovery console
Select root shell

mount  

Should give you some output, you're looking for the one that has on / type in it.

/dev/sda7 on / type ext4 (rw,errors=remount-ro)

You need to remount it read-write:

mount -o remount,rw /dev/sda7

Now we need to find the driver to uninstall:

jockey-text --no-dbus -l  

Don't worry abound the error messages, you want the last two lines
One of them should read something like:

xorg:nvidia_current - something (Proprietary, Enabled, In use)

or

xorg:nvidia_current_updates - something (Proprietary, Enabled, In use)

You want whichever one is Enabled

jockey-text --no-dbus --disable=xorg:nvidia_current
sync
init 6

It should reboot you in to a GUI now using the noveau open source driver.