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I was upgrading to ubuntu 12.10 from ubuntu 12.04 lts. After the download during the installation period, the computer's screen got locked and when I tried to unlock the screen, the black screen continued. So I switched it off and when I turned it on back again, it showed that ubuntu is running on low graphics and I need configure it manually. I tried the "run in low graphics for one session" option, but the screen just got dark. Please help. I am using Asus Eee PC.