My problem is that i had already installed it in a pendrive, but i formated my lap top and the pendrive, i didn't uninstall ubuntu. When i finished installing the new OS i installed ubuntu again in the pendrive. When i tried to update ubuntu i had problems and i decided to download the latest version. I formated the pendrive again, but when i tried to install ubuntu 12.04 LTS the installer told me that i have already intalled ubuntu and the installation can't advance. Also when i turn on my computer when i have to select an OS there are two ubuntu options, how do i get rid of that?