Can I (if so how) uninstall windows after completely installing Ubuntu 12.04 from a USB boot drive?

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http://askubuntu.com – I have successfully installed Linux Ubuntu 12.04 of my computer with the USB boot method. When I installed Ubuntu, I selected the option where it lets you keep windows on the computer in a separate partition so that you can have both Linux and windows as operating systems in the computer. Well, I decided I no longer need Windows, and I very much want to remove it so Linux has more space. Can I remove windows at this point and allocate more space for Linux, and if so, how can this be done? Thank you. (HowTos)