Step 1: Format the Drive
Just place the flash drive in the USB port of your computer. Open command prompt (cmd). You can do that by pressing WINKEY+R, right click on the listed file and click on “Run as administrator“.
Enter the following commands in the same order as I did here:
diskpart list disk select disk z (where z is the number corresponding for your USB disk. You have to replace it with the corresponding letter from your own system). clean create partition primary size=5000 active format fs=fat32 quick assign exit
Note the size in the command “create partition primary size=5000” is in MB.
Please be careful using the select command (so you don’t select and format your hard disk instead)
If everything goes well, this is how your cmd screen will look like
Step 2: Mount The Windows 8 ISO Image Into A Virtual Drive
If you don’t have a physical optical drive you should mount the image into a virtual drive. You can install and use PowerISO
Step 3: Make The External Hard Disk Bootable
I’m assuming that F is your drive letter with Windows 8 ISO image and G: is the location of your external hard disk (or flash drive) . Open the command prompt screen (as administrator) and type the commands:
F: cd boot bootsect.exe /nt60 g:
Also, don’t forget to triple check the target location so you don’t accidentally delete the boot sector of your hard disk
Step 4: Copy The Installer Files
After the above step, don’t close the command prompt (at least not yet). At this moment your new external hard disk or flash drive is bootable but you need to execute one more command in order to transfer the files to your new drive. You have to type the following command line:
xcopy f:\*.* g: /e /f /h
Again replace the drive letters with the ones that apply to you. Alternatively you can copy all the files in the virtual drive to the flash drive or external hard drive by using Windows Explorer, but using XCOPY ensures that system and hidden files are also copied.