How to make Bootable usb Pendrive in windows 7

Today my friend asked me to install windows 8 which is downloaded from microsoft website, but he is not having any optical drive attached to his pc.

There is two options for me to install windows 8 in his system one is attaching optical drive and second is using USB pendrive, so i think of doing it with pendrive. If i wnat to install windows from pendrive, i have to make it bootable. There are many tools available to create bootable pendrive, i also explained one tool called win2flash here How to install Windows from usb Flash drive. But i dont want to use any tool, so i followed the below commands to make pendrive bootable, iam running windows 7 in my system.
You can also follow the steps to make pendrive bootable.

Tools Required
1. USB flash drive with a minimum of 4GB capacity
2. Windows 8 ISO image file.
3. Virtual Clone Drive (used to mount .iso image file)
     My previous post How to open ISO image files can help you to download it.

Step 1 : plug in USB flash drive.
Step 2 : Open command prompt from start> All Programs> Accessories> Command Prompt.
Step 3 : at command prompt type the command
               DISKPART
This will start Microsoft Diskpart utility as shown

Now enter the following command
    LIST DISK

This will show you the available disks on your system, Usually Disk 0 is Hard disk, Disk 1 is usb flash drive (in my case Disk 1, this may diffenent in your case).

Now enter the command
 SELECT DISK 1

Step 4 : Now enter the following commands one after one.
  CLEAN
  CREATE PARTITION PRIMARY
  SELECT PARTITION 1
  ACTIVE
  FORMAT FS=FAT32
  ASSIGN
  EXIT

Thats it now your USB flash drive is bootable.
Step 5 : Now mount your windows 8 image file using Virtual Clone Drive.
Step 6 : Copy the entire content of the mounted dick in to your usb flash drive.

Your USB flash drive is ready to boot and install windows 8.
change your Bios settings first bootable device to your usb flash drive.