HOW TO MAKE FLASH DISK BOOTABLE

Bootable USB guide

 In this guide we assume you are using windows Vista or windows 7,8 or 8.1.
1.Insert your USB  flash drive(most likely 4GB or preferable) to your computer
2.Open Command prompt by pressing start menu and type cmd then run as administrator
3.After CMD opens, Enter the following commands followed by hitting Enter Key
     diskpart           
     list disk                                                

After you entered list disk command,The list of disk attached to the computer will be displayed.
On consideration to the below attachment, USB drive disk no is disk 2
 4.Now from here you only need to enter commands one by one followed by pressing Enter Key.
select disk 1
clean
create partition primary
                                                 select partition 1
                                                 active
                                                 format fs=ntfs quick
                                                 (format process may take few seconds)
                                                 assign
                                                 exit
                      On that approach your USB flash drive is ready as bootable drive
                      Now you can copy windows file to your USB flash disk and perform windows installation
                      NOTE:this bootable flash guide will not work out for windows XP
                      For the case of how to create bootable flash disk for Windows XP this link would be helpful   for you to download the required tool  http://www.pendrivelinux.com/universal-usb-installer-easy-as-1-2-3/