I’m writing this because I can, for some reason, never remember how to use Diskpart. And who uses DVD’s anymore? Download the Windows 10 preview ISO from here: http://windows.microsoft.com/en-us/windows/preview

Insert a usb drive at least 4gb in size

Open a command prompt as administrator

Hit Windows Key, type cmd and hit Ctrl+Shift+Enter. This will force it to open as admin.

Run diskpart

This will open and run the Diskpart command line utility, which allows you to manage disks, partitions and volumes.

C:\Windows\system32> diskpart

Run list disk

This will list all disks on your system. You’ll see the something similar to this:

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          238 GB      0 B
  Disk 1    Online          465 GB      0 B
  Disk 2    Online           29 GB      0 B

Select your flash drive by running select disk #

Find the item that corresponds with your flash drive and select the disk. In the example above, my flash drive is disk 2 so I’ll run:

DISKPART> select disk 2

Disk 2 is now the selected disk.

Run clean

WARNING: This deletes all data on your drive

The clean command marks all data on the drive as deleted and therefore removes all partitions and volumes. Make sure you want to do this! If you are sure, run:

DISKPART> clean

Create a partition

 DISKPART> create partition primary

Select the new partition

Since we know there is only one partition, we can just run this:

DISKPART> select partition 1

Without checking the partition number. If you’re really curious, run list partition to check.

Format the partition

To format it, we’ll use the NTFS file system and run a quick format:

DISKPART> format fs=ntfs quick

Set the current partition as Active

Run:

DISKPART> active

Exit diskpart

Run exit. This will exit diskpart, but leave the command window open.

Mount your ISO

Use Virtual CloneDrive or similar.

Navigate to the mounted image and install a bootsector

My ISO is mounted as G:\, so I’ll navigate to G:\boot and run:

C:Windowssystem32> G:
G:\> cd boot
G:\boot> bootsect.exe /nt60 E:

Where E:\ in this case is my flash drive’s letter.

Copy the entire contents of the ISO to your flash drive

You can either do this from Windows using Ctrl+C+Ctrl+V, or from the command line using xcopy.

G:\> xcopy g:\*.* e:\ /E /H /F

/E copies all subfolders, /H copies all hidden files and /F displays all source and destination file names as it’s copying.

Once that’s done, go and install Windows!

Source: https://davidzych.com/install-windows-10-from-a-usb-flash-drive/