The need to install Windows 8 or Windows 8.1 from a USB device, like a flash drive, is a common one these days.
It's no surprise why - many new computers, especially tablets and smaller laptops and desktops, no longer have optical drives.
Here let’s introduce some ISO to USB utilities.
1. Rufus, a free tool that will correctly prepare the USB drive, automatically extract the contents of the ISO file you have, and properly copy the files contained within it to your USB device, including any files in the ISO needed to make it bootable.
2. UNetbootin, can create a bootable Live USB drive, or it can make a "frugal install" on your local hard disk if you don't have a USB drive. It loads distributions either by downloading a ISO (CD image) files for you, or by using an ISO file you've already downloaded.
3. ISO to USB, a free and small software that can burn the ISO image file directly to the USB drives, these USB drives include USB flash drives, memory sticks and other USB storage devices, it also supports to create a bootable USB disk with Windows operating systems.
4. Universal USB Installer, a Live Linux USB Creator that allows you to choose from a selection of Linux Distributions to put on your USB Flash Drive. The Universal USB Installer is easy to use. Simply choose a Live Linux Distribution, the ISO file, your Flash Drive and, Click Install. Upon completion, you should have a ready to run bootable USB Flash Drive with your select operating system installed. Other features include; Persistence (if available) – note that casper persistence will only work with fat16 or fat32 formatted drives.