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I have an ISO image of the Windows 7 installation DVD, but I can't burn it to CD or DVD. I have an empty flash drive with plenty of space. Is there any way I can put the ISO image on it and install from it as if it were a CD?

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isotousb.com is a simple tool for this purpose –  fozylet Aug 9 '12 at 1:01
@nateify This may also be a viable alternative/solution intowindows.com/… –  Simon Dec 18 '13 at 15:42

8 Answers 8

up vote 51 down vote accepted

Microsoft has released a tool to put an ISO of Windows 7 on a bootable USB drive (or on a DVD).

Windows7Hacker has an explanation on where to download this tool and how to use it : Creating Bootable Windows 7 Install USB Flash Drive or DVD Using Windows 7 USB/DVD Download Tool

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Do you happen to know if one can install Grub2 loader to USB after creating this bootable USB? Would be nice to have a possibility to run Live Linux or install Windows. –  dma_k May 22 '14 at 19:50

Here's the method I use, it seems to work on more flash drives than other methods (especially if the partitioning or formatting of the drive got messed up). This also works with Windows 8 and Windows 10.

1. Start an elevated command prompt (i.e., run the command prompt as an Administrator)

2. Clean, partition, and format the USB drive with diskpart

  1. Run diskpart
  2. Type list disk to see which disk number your flash drive is
  3. Type select disk #, where # is the number from step (2)
  4. Type clean to clear the drive
  5. Type create partition primary
  6. Type select partition 1
  7. Type active to make the partition active
  8. Type format fs=fat32 to format the partition
  9. Type assign to finish and let Windows assign a drive letter
  10. Type exit to leave diskpart

3. Set up the boot sector with bootsect

  • Run X:\boot\bootsect.exe /nt60 Y: where X is the Windows disc* and Y is the flash drive

  • Note: Use /nt52 instead if you're doing this process for XP! Bootsect.exe doesn't come with XP, though, so you'll still need a Vista or 7 disc to get a copy of bootsect.

4. Copy the contents of the Windows DVD over to the USB drive

  • You can use xcopy to ensure the files are all copied properly: xcopy X:\* Y:\ /E /H /J /K /V (note that this doesn't do CRC checking or anything extensive, but what's the chance you'll need that?)

I originally learned this method from "Kevin's Blog", so credit to him.

* I like to mount ISOs with Daemon Tools, the free version is fantastic. You can, of course, use WinRAR or something to extract the DVD instead; just replace X:\ with the path to the extracted folder.

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Thanks, this worked for me after other methods failed. –  James Feb 5 '12 at 9:05
@Matthew Read - Hey, I followed these steps and whe nI try to boot from the USB drive I get "NTLDR is Missing". Any ideas? This is with a Windows XP Pro cd. I made sure to use bootsect with the '/nt52' parameter. (I grabbed bootsect from my Win7 x64 cd, but I also tried an x86 one I found online) –  Pandincus Feb 10 '12 at 6:02


Easiest way is to mark a partition as active (although not always needed, depending on your motherboard).

Next, extract everything in the ISO to the root of the USB drive (use Winrar, 7-Zip or your favourite extraction program.).

Reboot and either change boot order in the BIOS or press whatever key it is on your motherboard to bring up the boot menu (usually F12 or Esacpe).

Choose USB drive.


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Can you just quickly mention how to mark a USB drive partition as "active"; I've not heard of that before. –  Neil Barnwell Jul 19 '10 at 11:21
@Neil Barnwell, you simply go to disk management or any partition management tool and just set the drives partition to active in the same way as you would a hard drive. In Windows disk Management, right click and choose Active. –  William Hilsum Jul 19 '10 at 12:29
Your solution doesn't address making sure a proper boot sector exists on the USB key, which I believe is necessary for it to boot. @Matthew Read's solution does address this. –  ultrasawblade Jun 24 '11 at 16:15

Use UNetBootin to create a bootable USB flash drive with the ISO.

The software was made for creating bootable linux flash drives, but works with any bootable ISO.

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Doesn't detect my Transcend 250GB external HDD :( –  Bogdan0x400 Jun 24 '11 at 15:36
@Bogdan0x400, open the command prompt, cd to the folder where unetbootin.exe is located and start it with the option "targetdrive=f:" unetbootin targetdrive=f:" (replace "f:" with your drive's letter) –  sm4rk0 Feb 20 '13 at 0:24

If already running Windows™ you can simply use the Windows 7 USB/DVD Download Tool from Microsoft.

If on another OS you can perform the following steps:

  1. Make sure the filesystem is NTFS and has the bootable flag set..
  2. Use ms-sys to write boot record (ms-sys -7 /dev/sdx).
  3. Mount the ISO and copy all the files and directories.
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I know this question is a few years old, but I think this program is worth mentioning (it's also easy).
Your Universal Multiboot Integrator
YUMI Multiboot USB Creator
You can use it to add many Operating Systems on one flash drive (both Windows and Linux, I don't know about MAC OSX) You can also use it to add other ISO images, like Norton Ghost SRD, Acronis True Image and many other tools. YUMI list of available ISOs!

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Here you go, in four easy steps:

  1. Using the HP USB Disk Storage Format Tool (v2.0.6), format the flash drive using FAT32 leaving all the boxes unchecked.

  2. Mount the Windows 7 ISO image using Virtual CloneDrive (a free tool).

  3. Then copy the contents of the ISO image (all of the Windows 7 files and folders) over to the flash drive. Grab a cup of coffee; it could take upwards of 5-10 minutes.

  4. Lastly, rename the file on the root of the flash drive from "BOOTMGR" to "NTLDR".

I hope this helps...

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Almost a copy of my answer, anyway - I don't think step 4 is needed - I have never needed to rename anything and I do not recommend step 2. Any sort of Virtual drive program installs a driver which will always be running and slow your machine (although not exactly by a lot, and I do like virtual clone drive). If this is a one off job, it is much better just to use Winrar or 7 zip as I said. It will dothe same job and will not do anything to the system. –  William Hilsum Oct 28 '09 at 20:48
I don't understand how it is almost a copy of your answer, anyway - thanks for the critique... lol –  pjemmert Oct 28 '09 at 20:58

I love using rufus for extracting any OS onto a USB. It's source is on github as well.

Rufus Source on GitHub

Rufus Download

Rufus UI

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protected by nhinkle May 20 '11 at 3:38

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