Black screen after updates

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http://askubuntu.com – Today I accepted some automatic updates on Ubuntu 12.04, and after closing my laptop, the screen was black and Ubuntu was unresponsive. Since then when I reboot I get the Ubuntu splash screen and then it goes back to the black screen and I can't do anything. I've tried rebooting it in recovery mode and this doesn't help. What steps can I take to diagnose and hopefully fix this problem? (HowTos)