How to install an OS from a USB


It’s going to happen more and more often as we move into the age of tablets. Those of us who remove, change, or reinstall our operating systems find it more or less annoying that many systems, such as netbooks and tablets, don’t come with a DVD drive. Sure, you can buy a USB drive and install that way, but they’re pricey, and just another thing to have to carry around.

Installing your OS from a USB drive isn’t hard, if you are willing to play around with the command line a bit. You can also use Microsoft’s Windows 7 Download Tool, but I’ve found it doesn’t like my ISO of Windows 8 very much. Also, I just prefer the command line.  Before you get started, consider the size of your installation.  Windows XP, Vista, and 7 can all be loaded onto a 4GB drive, but you’ll need an 8GB to fit W8.

The first thing you have to do is put your OS disk in your computer’s dvd drive. If you have an ISO file, you’ll need software to mount it as a virtual disk. I suggest MagicDisc, as it’s free and easy to use. Now, time to get that command line going. Locate C:\Windows\System32\cmd.exe, and right click it. Choose the option to send a shortcut to your desktop if you wish. Either way, you’ll need to select Run as Administrator for this particular tutorial. Now would be a good time to insert your USB stick into a port and take note of the exact size, so as not to confuse it with any other drive on your system.

Alright, next thing you need to do is type “DISKPART”, all caps or all lowercase is fine, CMD doesn’t care either way. It will load after a second or two, and you’ll be met with a blinking line after Diskpart. If everything is good so far, then proceed to inserting the following commands in bold, pressing “Enter” after each one:

Disk list

You will get a list of available drives, take note of which drive is your USB. Most of the time Disk 0 will be your HDD, and as you can see Disk 1 is my sacrificial USB drive for this tut. I usually unplug all unnecessary drives when I do this.

Select disk # (# being your disk number)


Create primary partition

Select partition 1


Format FS=NTFS

This part takes a while depending on the size of your drive and how fast your port is. I’m using a 16GB drive in a USB 2.0 port, and it takes about 30 minutes or so for a full format. I’ve had much quicker sessions using a USB 3.0 configuration. Okay, when the format is all done, finish up with two more commands.



Now you should be out of Diskpart. Next thing you need to do is navigate to the drive where your OS disk is. I’m using a virtual disk mounted at E:, so I would use the following command:

cd E:\boot

Substitute your drive letter here, and then type in the following command:

Bootsect.exe /nt60 G:

G: is the location of my USB drive. Substitute your drive’s location instead. Bootsect infuses boot manager compatible code into your USB key to make it a bootable device. Another thing, if you’re using a 32-bit disk, use a 32-bit bootsect. The same goes with 64-bit. Just like many things in the world of computing, mixing and matching isn’t a great idea.

Now, the only thing left to do is put all the files on your USB drive. Go to Computer and right click the drive where your OS disk is mounted and click Open. Then copy everything in there over to your USB drive. Congratulations, you just created a bootable USB drive loaded with your operating system! Now make sure the system you are going to install it on is set to boot via USB in the Bios and you’re good to go.

Happy installing.


Don is an avid gamer, writer, screen writer,part time game maker, film director, and horror film fanatic. You can check out his book "How to Survive Zombies and Other Disasters" on Amazon.