Rufus is a free, portable open-source utility that you can use to create bootable USB flash drives. Actually, all you need is a USB with a good capacity and a utility like Rufus.
Have you ever been faced with the need to install a new operating system on a crashed PC but realize that you don't have the installation disc? For most people, such a case is always discouraging and disheartening because they know that the only way to install a new OS is to use an installation disc.
