Creating the Windows 8 Bootable USB Drive
Step 1: Download and extract WinUSB Maker on your computer. WinUSB maker is a portable application and thus does not require installation of any kind. You only need to run the .exe file.
Step 2: Run the WinUSB Maker tool with administrative privileges to start creating your bootable USB drive. (right-click on the file, and click Run as Administrator)
Step 3: In the tool, select the option ISO image bootable disk under the Functions section. Select Normal Detection Mode and browse for the Windows 8 bootable ISO (Image file) you have already downloaded on your system.
Step 4: Finally, select the USB drive and drive MBR system (if you have a single one plugged in, it will be selected by default, if you have more than one, click on the dropdown menu and make a selection from the list) and click on the button Make it Bootable .
You can now plug in the device into your system and select removable drive as your first boot selection preference in your BIOS and install Windows 8.