How do I recover from an nvidia graphics update?

How do I recover from an nvidia graphics update?

How do I recover from an nvidia graphics driver update. It prevents my
system from booting to the desktop. I have been reading and trying dozens
of so-called "fixes" for days and NONE of them allow me to get beyond
where it says "mountall: disconnected from Plymouth". Even the Live CD
desktop is unviewable. Do I need to reinstall and skip the update next
time? or what? I am using 12.04 LTS with Nvidia GeForce 7025 / n630a.
Thank You for any real help, if there is any.