[ubuntu] unmounting problem

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http://ubuntuforums.org – Sorry for the noob question, just switched from windows and never used any kind of linux before. So I finally got Ubuntu 12.04 installed and working (despite having broken optical drive and failing at the usb method) but now I want to get rid of windows 7. Downloaded Gparted Partition Editor and I "Think" Sda2 is the one I need to wipe but it is mounted and when I try to unmount it through Gparted I get: Could not unmount /dev/sda2 umount: /host: device is busy. (In some cases useful info about processes that use the device is found by lsof(8) or fuser(1)) So then (Hardware)