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i have installed Ubuntu 14.04 in dual boot with windows 8.1 and want to know as to if ever in future if i need to remove Ubuntu . how will i do that? please help.
I guess you can't uninstall it but delete the partition of ubuntu.
Boot from live usb/cd of ubuntu or if you still have your windows. Delete the ubuntu partition.
I'm not an experienced user, so i'm sorry if something goes wrong.
Boot into windows, and use the windows computer manage tool to remove the ubuntu partition. In your windows explorer, right click on "This PC" and select "manage" from the cascading menu. Select the Storage>Disk Management section in the menu on the left hand side, and find the partitions which contain your linux info. There will be a number of them, and windows will say they are unidentified or something. Then, you will need to repair your Master Boot Record so you don't fail loading the linux boot software you just removed. To do this, follow the instructions here. All said and done, it's kind of tedious but not at all difficult.