I'd use WinToFlash. It enables you to copy Windows installation sources to bootable USB:
WinToFlash is likely to make a big difference to the way you work. It will make life a lot easier for you. Quickly and simply install the program you needs and in no time at all you will find yourself writing essays on Windows and using your USB. The WinToFlash makes the job hassle free for you.
WinToFlash is software for transfer your Windows XP, Windows 2003, Windows Vista, Windows 2008, Windows 7, Windows 8 Setup from CD or DVD to USB in some mouse clicks. This is about you can install your Windows from flash drive or card, HDD, etc. to your computer or netbook.
And this is not all it can do. WinToFlash can transfer your live CD or DVD to USB card, for example, BartPE. After all you can erase your USB media and format it with Windows for everyday use.