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I had downloaded Ubuntu 12.10 several times and I tried to install it with USB stick and CD (or DVD) but I experienced several errors. I had a Ubuntu 10.10 DVD, so I have just installed it. But it seems Ubuntu 10.10's update and language support isn't working anymore.
So I've searched and tried everything to upgrade it, but I always run across a error saying 10.10's repositories no longer supported. Even I've just added 12.04's repositories and tried again, but I again run across an error saying the same thing.
So how can I upgrade Ubuntu 10.10 to 11.04?