First, this will erase everything on your flash drive and if you're not careful, you can delete your data from your other important devices. Do this only if you know what you do!
First we need usb flash drive, which is at least 4GB and contains no important data (if yes, first copy them and not the drive where you plan to install Windows 7!). Secondly we must do it on a computer that supports Vista or later (Windows 7 works well there, but XP and previous Windows does not). Now open your changes and enter the command (remember to press enter after each command):

