There are basically two easy methods to create the bootable windows 7 USB flash drive. The first method is simply using CMD window with some commands and the second is using a microsoft’s windows 7 USB DVD download tool. The methods are as given following …
1) First of all open the CMD window (Command Prompt Window, if you use UAC make sure to right click it and choose “Run as administrator”).
Now type “disk part” without the quotation marks and hit enter. You can also get here by simply typing “diskpart” without the quotes.( refer fig.1 )
2) The second command is “list disk” ( refer FIG. 2). Now enter that command without the quotes and press enter. Take a look at the Size column and figure out which disk number your USB drive is. Ours is number 1, so we’re going to type “select disk 1” without the quotes and hit enter. Now we are going to wipe it by typing “clean” command without the quotes and hitting enter (make sure to do a backup of the contents if you haven’t already) .( refer fig. 3)
3) At this point we want to prepare the USB drive for the files and make sure it is bootable. Type “create partition primary” without the quotes and hit enter. Then type “select partition 1” without the quotes and hit enter. Next type “active” without the quotes and hit enter. Finally, type “format fs=fat32” without quotes and hit enter (if you choose to use ntfs, you’ll later have to run the “Bootsect.exe /nt60 G:” command to put boot manager compatible files onto your USB flash drive to make it a bootable device). When it’s done then type “assign” command without the quotes and hit enter (this will assign a new drive letter to the USB flash drive). ( refer fig . 3)
An AutoPlay window like the one above will appear. Remember the drive letter (here its H:) then close the window, type “exit” command without the quotes and hit enter. If you are working with an .ISO image, the best way to do this last part is to mount the file with a program like VIRTUAL CLONE DRIVE. Alternatively, you can extract the files from the .ISO image and simply copy them to the USB drive, but since we’ve been using the command prompt up to this point, we’ll show you how to do the last step with it as well.
If you don’t have the command prompt open, open it with administrative privileges, type “xcopy f:*.* /s/e/f hg:” without the quotes and hit enter. Note that you will likely have to replace “f:” with the drive letter for your Windows 7 DVD and “g:” with the drive letter for your USB flash drive. Don’t worry if install.wim takes a while to copy.
AND IT’S DONE .. !