How to Create a Bootable USB Flash Drive in Windows 7

Need to create a bootable USB flash drive to install Windows 7 on other PCs or on your ultralight laptop or netbook that came without an optical drive?

I found many tutorials on the net that showed a method using the well-regarded commercial product "UltraISO," but I wondered if the built-in commands and programs already in Windows 7 and/or open-source, free software would allow me to do the same.

The answer is "Yes!"

The program on the Windows 7 or Vista PC is called "diskpart.exe." With it and a Windows 7 DVD or ISO image file, and using the free burning program ImgBurn if necessary, one can create a bootable flash drive (4 GB or larger) without using any other tools. Here we show you how.

If you dowlnoaded the release candidate version (RC) or the release to manufacturing version (RTM) and have the .ISO image file on your PC, you will need to burn it to a DVD for this process to work as described. ImgBurn is a good choice for this. With a blank DVD in the drive, right-click the ISO file and select "Open with... ImgBurn." Then click the green icon at the bottom to start creating the Windows 7 disk.

When finished, you'll be able to go to "Computer" and "Open" a window on the contents of the DVD.

Of course, if you have the Windows 7 production disk, that's great.

This procedure will definitely erase everything from the flash drive, so if you have anything at all on it you want to save, click on Computer, click the flash drive icon, and drag the entire thing out to your desktop.

Once you have the drive backed up, reinsert it into the PC, and you'll be ready to continue.

diskpart.exe is a command-line interpreter used for managing partitions, disks, or volumes in Windows XP and newer versions. It's an adjunct to the graphical (GUI) disk management provided by the Windows "Disk Management" applet, which is designed to be pretty much goof-proof.

DiskPart is not goof-proof, so please read through all the following steps and make sure you understand the sequence before starting.

Some users may be unfamiliar with using a multi-line interactive application in a DOS window. This simply means that the program acts on the commands you enter and then presents a menu for further actions.

Also, please note that the procedure has to be started and completed on the same computer. (If the computer has a poorly performing DVD drive that gets read errors, the procedure may well fail. In this case, we suggest that you try on another, maybe newer, machine.)

You'll need administrative permissions to do this, so start by selecting All Programs → Accessories and right-click Command Prompt and select "Run as administrator."

Then type in "diskpart." The program will respond by creating a "DISKPART>" prompt.

Enter

list disk

at the prompt. Note that "disk" is not plural in the command. In the image below, the flash drive is showing up as 7646 MB, and yes, that's the flash drive. The first drive (C:) is listed as Disk 0, so on this PC, the flash drive is Disk 1.

Most of the commands in DiskPart apply only to the drive or partition that has focus or is selected. This is denoted by an asterisk beside the partition name. To give the flash drive, which is Disk 1 in this example, the focus enter

select disk 1

The next step is to remove any volume or partitioning information from the flash drive. Since Disk 1 (or whichever disk number is the flash drive on your PC) still has focus, the command

clean all

applies to the flash drive only. This step "zeroes out" all the data on the drive, so it takes a while to run. (The larger the flash drive, the longer, of course.) Note also that DiskPart gives no feedback about progress. When the light on the flash drive stops flashing, the prompt will return.

Next: Continuing preparing the flash drive, copying the install files, and using the bootable flash drive to install Windows