reset video driver to original ubuntu driver

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http://askubuntu.com – I have an nVidia and I installed the latest drivers from the nVidia web site. I then forgot to uninstall the driver before taking tons of updates and ended with an unbootable Ubuntu installation. Following directions from this page I managed to mount and get into the broken Ubuntu installation using the Ubuntu 11.10 LiveCD. Now the question is how can I remove the nVidia driver and reset it to the original Ubuntu installation via this Chrooting access? For example, if I run the steps here it won't work because the commands apply to the host running Ubuntu which is the one from the LiveCD and (HowTos)