Ubuntu won't boot how to uninstall nvidia driver?

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http://askubuntu.com – I had Ubuntu 3.0.23 and installed manually the nVidia drivers 2 months ago. Now took the accumulated updates 3.0.26 and can't boot anymore. After the GRUB menu I get a black screen and a cursor. Is there a way to get into the system and remove the nVidia driver?. I have tried booting with both kernels and also the recovery mode but doesn't work. (HowTos)