Install Windows 10 from a USB Flash Drive

Steps

1. Insert a usb drive at least 4gb in size 

2. Open a command prompt as administrator.
Hit Windows Key, type cmd and hit Ctrl+Shift+Enter.
This will force it to open as admin.

3. 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

4. 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 8 GB 0 B

5. 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.

6. 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

7. Create a partition 

DISKPART> create partition primary

8. 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.

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

DISKPART> format fs=ntfs quick

10. Set the current partition as Active 

Run: DISKPART> active

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

12. Mount your ISO Use Virtual CloneDrive or similar. 

13. 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.

14. Copy the contents
To 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

/Ecopies 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!


*****NOTE*****

- Use Fat32 for UEFI+Secure Boot installations and it works. UEFI booting requires FAT32.
- 32 bit version of windows and, if so, you can't run 64 bit software.
- If you encounter at step 10 DISKPART> active     

     Error:
     The selected disk is not a fixed MBR disk.
     The ACTIVE command can only be used on fixed MBR disks.

     run DISKPART> exit
     redo all steps until 8, after DISKPART> clean is successful
     run following DISKPART> convert MBR, continue with step 8 and the rest described here