Installing Windows 7 from a USB drive

Yesterday, Windows 7 RC (release candidate) was published on MSDN, so the subscribers are currently downloading it. I have been using Windows 7 since October 2008, when it was pre-released during the PDC conference. Then I moved to the beta when it was released, and have been using it as my main system since then. I almost never had to go back to Vista (which I kept installed on another partition of my main laptop, just in case).

By a funny coincidence, though, Win7 beta stopped working for me last night, after a nasty crash that aparently corrupted the user profile. This would be possible to fix, but I decided what the heck, all my data is safe anyway (I have a 3rd partition for data, plus back everything up to Mozy) so it's not like I really need to go back into Win7 beta, especially since the RC is almost there.

So now I am eager to install. The bits are currently being downloaded, and I have a couple of hours to kill while waiting. So why not study an alternative way to install Win7 to a PC? At the last MIX, I remember I heard someone mention that you don't need a DVD to install Win7. A simple UBS stick is enough, provided it is big enough to hold the 2.5 GB data contained in the Win7 ISO file. Well it so happens that we got a free 4GB USB stick at MIX, so here we go, perfect conditions for the test :)

I searched online, and found this gem of a video, by Dennis Chung, one of the DPE in Singapore, that shows in details how to do that.

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To make it even easier, here are the steps:

Preparing the USB stick

  1. Plug the USB stick in a USB port, and make sure that you don't have any data you need on it. The data will be erased.
  2. Open a command line console
  3. Type Diskpart
  4. Type List Disk
  5. Type Select Disk N where N is the number corresponding to your USB disk. This should be easy to find based on the size of the disk.
  6. Type clean
  7. Type create partition primary
  8. Type active
  9. Type format fs=fat32 quick
  10. Type assign

After this is done, you should see the USB disk appear in Windows Explorer in the list of mounted drives:

Copying the files

Then, you need to mount the ISO file as a virtual DVD drive. For this, you will need a 3rd party tool. Personally, I like VirtualCloneDrive. Simply copy all the content of the ISO file (mounted through VirtualCloneDrive) to your USB stick.

Booting

In order to boot from the USB stick, you need to modify the boot order in the BIOS of your computer. Accessing the BIOS menu depends on your machine. On my Alienware M15X, I need to press XXXX while the machine is starting up. This gives me access to the BIOS options, where I can select the boot sequence. If the USB stick is found, the laptop will boot from there.

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Note: To speed up the boot sequence, revert the setting to always boot from the hard disk after you are done installing Windows 7.

With this done, you should now see your Windows 7 installer starting up and leading you through the installation process. Have fun!!

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Print | posted on Friday, May 01, 2009 11:20 AM

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# re: Installing Windows 7 from a USB drive

left by joe at 5/1/2009 12:39 PM Gravatar
This has worked since Vista, and I use it for Server2008, Vista, and 7. You have to use "diskpart" from Vista (or later) OS (I believe).

PS: Windows 7 can mount ISO images, so you will no longer need Virtual Clone Drive in the future.

# re: Installing Windows 7 from a USB drive

left by lake393 at 5/5/2009 7:50 PM Gravatar
Great, I'll do this at home tonight. I've done this before, when I was on Vista and had to prepare a USB stick install of WinServer2008 for a server, but it was a year ago and I forgot the instructions. Thanks for making such a clear set of instructions.

Good thing I will be preparing the USB stick from Win7beta, because Joe is correct--- Diskpart in WinXP does NOT have this capability. I have empathy for anyone on WinXP who is trying to look for a way to do this. I feel your frustration.

# re: Installing Windows 7 from a USB drive

left by Juan T. Llibre at 8/11/2009 5:03 AM Gravatar
Laurent :

Using Windows 2008 R2, I wasn't able to get setup to boot...until I physically copied the files to the USB.

Virtual Cloning doesn't kick in until an OS is running.

After formatting with DISKPART, I used Magic Disk to mount the Windows 7 RTM ISO file...and copied all the files to the USB...and then booted, after setting the boot priority to the USB device.

That worked like a charm.

The procedure described here failed.

# re: Installing Windows 7 from a USB drive

left by Laurent at 8/11/2009 8:20 AM Gravatar
Hi Juan,

I am sorry if it was not clear. I am not using virtual cloning. I am using VirtualCloneDrive to mount the ISO (it is an ISO mounted like Magic Disk) and then I copied the files physically from the mounted ISO to the USB stick. So I think I pretty much did what you did (and apparently I didn't explain it well enough in the article :)

Cheers,
Laurent

# re: Installing Windows 7 from a USB drive

left by online backup at 9/18/2009 6:26 PM Gravatar
It's great i will try to do this.
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