[ubuntu] Can't install ubuntu

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http://ubuntuforums.org – I'm trying to do a standard install of Ubuntu 12.4.1 on my computer after accidentally using Pen Drive Linux's USB Installer on my Ubuntu partition. When trying to install i get an error saying unable to unmount /cdrom device busy. Upon checking Gparted i see that sda5 (what use to be SWAP space before my accident) is mounted to /cdrom and sda5 and 6(ubuntu partition) are both labeled PENDRIVE and sda5 indeed can't be unmounted. So i tried the command Code: sudo umount -l -r -f /cdrom . No errors were given and upon checking Gparted is is indeed unmounted but i still can't format it (Hardware)