If you own a netbook or a laptop that lacks an optical drive, then you need a bootable USB to perform windows installation. If you have the operating system on a DVD and think that copying the files from the DVD to the USB will make it bootable, then you are mistaken. You need a specialized tool, such as, Novicorp WinToFlash to make a USB drive bootable.
WinToFlash supports a wide range of operating systems, including Windows XP, 7, 8 and the upcoming Windows 10. The procedure for making the USB drive bootable is very simple. All you need to do is select the ISO image of the operating system you want to boot using USB and the program will automatically copy the necessary files and make it bootable.
WinToFlash Lite is free to use, but lacks certain features like NTFS file system support and USB-FDD mode that are available in the professional edition.
The following offer from BetaNews will provide you with a professional license of WinToFlash, free of cost.
Download the license from here
Download the latest installer of WinToFlash from the developer homepage: http://wintoflash.com/home/en/
The professional license is valid for free usage until December 31, 2015.