How to create a Windows 7 / 8 Bootable USB flash drive

The fastest way for me to do this considering the machine does not have a DVD drive is to create a bootable USB flash drive with the Windows 8 installation files on. The process is pretty straight forward, but does require a little command line work.

a, First of all, you will need to download the ISO image of the Windows 8 Consumer Preview.

b, You will need to extract the files from the ISO image, so my preferred tool is SlySoft’s Virtual CloneDrive. This is free and easy to use. What it allows you to do is mount the ISO file as a drive. This will be needed later.

c, Now to format your USB flash drive. Keep in mind that this will erase all of the files on your USB flash drive, so you might want to double check it for important data before proceeding. Your flash drive should be at least 8Gb (especially if you are installing the 64bit version of Windows 8)

Plug in your USB Flash drive if you have not already done so.
Start a Command Prompt as an administrator (click the Start button and type CMD, right-click on cmd.exe and select “Run as administrator" and accept the UAC prompt, assuming you are using Windows Vista or Windows 7)

Type diskpart and then press ENTER For each line, type the parts on BOLD and press ENTER after each entry, the notes are for reference only
DISKPART> list disk (note: this will list the disks on your system. Typically look for the one that matches the capacity of your USB flash drive)
DISKPART> select disk x (note: x is the number for your USB flash drive you obtained from the list command above)
DISKPART> clean (note: this will erase your USB flash drive)
DISKPART> create partition primary (note: this will create a new primary partition on the USB Flash drive)
DISKPART> select partition 1 (note: this will select the partition you just created)
DISKPART> active (note: this will set the new partition as active, which identifies it as a valid system partition)
DISKPART> format FS=NTFS QUICK (note: this will perform a quick format on the USB Flash drive)
DISKPART> assign (note: this will assign a drive letter to the partition)
DISKPART> exit

d, Now we need to put the boot files from the ISO image you downloaded earlier on to the USB Flash drive. You will need to mount the ISO image using SlySoft’s Virtual CloneDrive. To do this, right-click on the ISO image you downloaded (i.e. Windows8-ConsumerPreview-64bit-English.iso) and select “Mount”. If you do not see the “Mount” option, it may mean that the Virtual Clone Drive (or similar) tool is not installed. Once you have selcted “Mount”, a drive letter will be assigned to the ISO image. Make a note as to what drive letter has been assigned to the ISO, in my case drive “F:”.
Next, you will need to start a Command Prompt as an administrator (click the Start button and type CMD, right-click on cmd.exe and select “Run as administrator" and accept the UAC prompt, assuming you are using Windows Vista or Windows 7).
Navigate to your ISO drive, in my case “F:” and type the following:
cd \boot (thanks Ron T for pointing this out)
bootsect /nt60 y: (note: where y: is the drive letter assigned to your USB Flash drive – this will copy across the boot files)

e, Lastly we will need to copy the installation files across from the ISO image to the USB Flash drive. To do this, type the following:
XCOPY X:\*.* Y:\ /E /J /H (note: where x: is the drive letter assigned to your ISO image and y: is the drive letter assigned to your USB Flash Drive)
You should note have a Windows 8 Bootable USB flash drive.