A USB thumb drive with Windows ISO on it can be used to install Windows newly or repair an existing installation of Windows. Such a bootable USB stick can be created easily on Ubuntu:
Prepare the ISO of the version of Windows you want to install or use. For example, the Windows 10 ISO can be obtained here. If you are upgrading from a Windows 7 or 8, you can find out which version you are allowed to upgrade to here (check the Upgrade Editions section).
An easy tool to create an installer USB thumb drive for booting Windows is WinUSB. It can be installed from a PPA:
$ sudo add-apt-repository ppa:nilarimogard/webupd8 $ sudo apt-get update $ sudo apt-get install winusb
$ sudo winusb --format /path/to/windows.iso /dev/sdc
Use the path to your ISO file and the device name of your USB drive instead of
/dev/sdc in the above command.
You should be able to boot up and install Windows using this USB stick.
Tried with: Ubuntu 16.04