Before continuing you will need the following:
If you intend to make your USB drive bootable, the BIOS need to support USB boot-up. To do so you will need to enter the BIOS and modify the boot sequence according to your preference. Usually this involves moving the USB drive up in the boot sequence and placing it before the hard drive. If all goes well, the computer should search the USB drive for boot instructions before the primary hard drive, if the computer doesn’t find a bootable USB drive, the comp/tools/Copying System Files to Make Bootableuter should continue the boot sequence without any problem.
Making a USB drive bootable can be done manually, but copying all the files and completing the steps in the correct sequence lends itself to making mistakes. Therefore, it is better to use a special USB boot utility such as WinToFlash to automate the process.