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I want to install Ubuntu from a Usb drive. It says I have to erase all my data but I want to install it along side Windows 8. The ""Install alongside windows" option doesn't appear. What appears is, "you don't have an operate syste etc, and Note: all your data will be lost." I've already installed Ubuntu on my Pc (alonge side windows 7) and it worked fine but I don't know now why is it not working on my laptop which is windows 8.