Categories Menu

Posted by | 209 comments

Make a Bootable External Hard Drive and Install Windows 7/8

Step 1: Format the Drive
Just place the flash drive in the USB port of your computer. Open command prompt (cmd). You can do that by pressing WINKEY+R, right click on the listed file and click on “Run as administrator“.
Enter the following commands in the same order as I did here:

list disk
select disk z (where z is the number corresponding for your USB disk. You have to replace it with the corresponding letter from your own system).
create partition primary
format fs=fat32 quick

Diskpart Bootable USB

Please be careful using the select command (so you don’t select and format your hard disk instead)

Diskpart External Hard Disk

If everything goes well, this is how your cmd screen will look like

Step 2: Mount The Windows 8 ISO Image Into A Virtual Drive

If you don’t have a physical optical drive you should mount the image into a virtual drive. You can install and use PowerISO

Step 3: Make The External Hard Disk Bootable

I’m assuming that F is your drive letter with Windows 8 ISO image and G: is the location of your external hard disk (or flash drive) . Open the command prompt screen (as administrator) and type the commands:

cd boot
bootsect.exe /nt60 g:

External Hard Disk Bootable

Also, don’t forget to triple check the target location so you don’t accidentally delete the boot sector of your hard disk

Step 4: Copy The Installer Files

After the above step, don’t close the command prompt (at least not yet). At this moment your new external hard disk or flash drive is bootable but you need to execute one more command in order to transfer the files to your new drive. You have to type the following command line:

xcopy f:\*.* g: /e /f /h

Again replace the drive letters with the ones that apply to you. Alternatively you can copy all the files in the virtual drive to the flash drive or external hard drive by using Windows Explorer, but using XCOPY ensures that system and hidden files are also copied.

Step 5: Boot Off The External Hard Drive or USB Flash Drive

To use and boot from your newly created drive on your netbook or computer, first you have to set your computer you must set it to boot through the USB flash drive. In order to do this shut down your computer, go in the CMOS setup by pressing the “DEL” or “F2″ key when the computer power on, without unplug the newly created external hard drive or USB Flash Drive from the machine. Set the device as the primary boot option, save the changes BIOS and restart. On newer computers you can boot from the device without entering into BIOS by pressing either “ESC”, “F9″ or “F11″ (different key on different manufacturers).

External Hard Drive bootable

Now you can install Windows as usual. Please be aware that if you’ve changed the boot sequence in the BIOS, remember to change it back as it was after copying the files (usually after first automatic reboot).



  1. Good post, Worked first time. Thanks.
    I used fs=ntfs, dont forget to use cmd as administrator.

  2. Really good write up. You saved me a lot of time and money.

  3. Access denied while run f:\>boot\bootsect.exe /nt60 e:

    • Make sure you run command prompt as administrator.

    • make sure you’re in the right directory

  4. Another way to go is to copy all the ISO files first to the external device then make it bootable running the following command:



    bootsect x:

    (where “x” is your external device’s drive letter)

  5. During boot, a message came out says: “Can’t find grldr”.
    I’ve copied all iso files to my external hard drive /main directory/, after I showed system and hidden files.
    How cud I solve such issue?
    Kindly help me.

  6. Yes! It works! Good manual

  7. Hi, just wanted to say thank you as this method worked perfectly. Now I can finnaly use my USB to boot my PC. Thanks again…

  8. Great, thanks a lot for the article. Saved me a lot of time.

  9. Nice instructions. They all worked and help me resurrect an old HDD that was giving me trouble to boot. Thanks.

  10. I would just use XCOPY f:*.* /e /f /h g: in step 4. To make /e /f /h actually working! Never the less, great tut thanks!

  11. everything works for me up until I get to the format fs=fat 32 quick. It say 0 percent completed virtual disk service error: The volume size is too big. I’m using a 250gb external hdd, please help.

    • If u are using fat23, ur hard-drive can not be bigger that 32 gb. You will have to shrink it, or convert it

  12. Tyler – I used fs=ntfs
    Handy for larger drives.

  13. format fs=fat32 quick, isn’t working. the volume is too big…

    • Cannot use fs=fat32 with large drive. Must use fs=ntfs

  14. i want to run my win from usb drive dont want to have an internal drive at all pls guide how to do it

  15. Thank you. If you cannot use format function trough cmd, what I did in my case i just right mouse click that hard drive in my computer and simply chose format than checked if setting were ok and formated again

    Right now finallising my copy of windows 7 to usb drive. I hope it will install on the same drive, as I don’t have any to spare… I hope it will work ;)

    • I tried that. Windows setup says “Windows cannot install with USB or IEEE 1394″
      So you have a bootable drive with no OS on it! Oh well! Good only if your system fails to boot from regular drive.

  16. I get all the way to finally making my drive bootable and I get “could not map drive to the associated volume device object: Access Denied”

    I’ve followed the tutorial to the letter.
    Please help?

  17. Actually scratch the above. I’ve followed the tutorial, but now I get so far as to plugging it into the computer that it needs to be the bootable drive on and the computer goes “no bootable device”.

    Please help!

  18. Hello! Your instructions seem really detailed. I have many staff in my drive (intenso 1 terra) though that i cannot delete, so i splited my drive in disk management so that i can use the second part and save my files to the one part. But when i started cmd and followed your instructions i noticed that my hard drive which is in disk 1 is not shown as 2 parts but as just 1 part. so if i continue how will it recognize the partition and work in the partition of the drive i want because i don’t want to lose my files? please help me friends……

    • The point of the command ‘list disk’ is to identify your usb drive. Once you see its number, that’s the number to use when you enter ‘select disk #’.

      This is important if you have more than one disk installed on your computer!

  19. i by mistake selected my hard disk and created partition primary and also selected it,,(i did all process except format) but i did not format it i cant see it in my computer….i cant open it !
    please help me…

    • Your main partition should still be there. You will need to identify it and then make it the ‘active’ partition.

      You try this by booting with cd linux, available with most magazines on linux, or if you have a repair cdrom for your OS you could try that.

  20. I tried to enter cd boot then it says the system cannot find the path specified how to solve? thanks

Post a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>