Can anyone provide detailed steps to install Windows 7 RC from a USB hard disk (rather than a DVD)?


4 Answers 4


Creating Bootable Vista / Windows 7 USB Flash Drive

This will walk through the steps to create a bootable USB flash drive for the purpose of installing a Vista or Windows 7 OS. These instructions assume that you have a computer with Windows Vista installed on it.


  • USB Flash Drive (4GB+)
  • Microsoft OS Disk (Vista / Windows 7)
  • A computer running Vista / Windows 7

Format the Drive

The steps here are to use the command line to format the disk properly using the diskpart utility. (Be warned: this will erase everything on your drive. Be careful.)

  • Plug in your USB Flash Drive
  • Open a command prompt as administrator (Right click on Start > All Programs > Accessories > Command Prompt and select “Run as administrator”
  • Find the drive number of your USB Drive by typing the following into the Command Prompt window:
    • diskpart
    • list disk
  • The number of your USB drive will listed. You’ll need this for the next step. I’ll assume that the USB flash drive is disk 1.
  • Format the drive by typing the next instructions into the same window. Replace the number “1” with the number of your disk below.
    • select disk 1
    • clean
    • create partition primary
    • select partition 1
    • active
    • format fs=NTFS
    • assign
    • exit
  • When that is done you’ll have a formatted USB flash drive ready to be made bootable.

Make the Drive Bootable

Next we’ll use the bootsect utility that comes on the Vista or Windows 7 disk to make the flash drive bootable. In the same command window that you were using in Step 1:

  • Insert your Windows Vista / 7 DVD into your drive.
  • Change directory to the DVD’s boot directory where bootsect lives:
    • d:
    • cd d:\boot
  • Use bootsect to set the USB as a bootable NTFS drive prepared for a Vista/7 image. I’m assuming that your USB flash drive has been labeled disk G:\ by the computer: bootsect /nt60 g:
  • You can now close the command prompt window, we’re done here.

Copy the installation DVD to the USB drive

The easiest way is to use Windows explorer to copy all of the files on your DVD on to the formatted flash drive. After you’ve copied all of the files the disk you are ready to go.

Set your BIOS to boot from USB

This is where you’re on your own since every computer is different. Most BIOS’s allow you to hit a key at boot and select a boot option.

  • I just moved my answer :-)
    – Ivo Flipse
    Commented Jul 29, 2009 at 13:30
  • 1
    Works like a treat. For those with little patience and/or slow thumb drives I'd recommend formatting the partition with format fs=NTFS quick. Commented Nov 11, 2011 at 14:30

Theres an excellent walkthrough at BlogsDNA

It basically uses MBRwiz to make the USB flash drive a bootable device. Is this going to be similar to what you refer as a USB hard disk?


Microsoft now have an option for downloading an ISO when you purchase Windows 7 and a tool for deploying that onto a USB thumb drive or DVD. Windows 7 USB/DVD Download Tool

  • What a nice and easy way!
    – mati
    Commented Dec 24, 2009 at 17:54

If you already have windows on the computer you wish to install it on, you can just copy the files from the DVD (or .iso using WinRAR) onto the flash drive and run the installer executable.

This might also give you a bootable flash drive, so you can use it if you don't already have a previous version of Windows on it, although I have not checked myself

  • It worked pretty well here. I used instructions that needed a little diskpart work and then it basically was just copying over files and booting from it. The worst thing to look out for is usually whether the computer actually boots from USB. Some weird Laptops (coughs ... Macbook coughs) don't.
    – Joey
    Commented Jul 16, 2009 at 5:53

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