How to Manually Create a Bootable USB disk for Windows 7 / 8 / 10 (UEFI / LEGACY)

Here is a tutorial on how to create a bootbale usb removable disk or flash for Windows 7, 8 or 10.
If you think an ISO file is a document for International Organization for Standardization, please stop reading here. :D

if your flash is already prepped up for booting in any of the chosen boot mode before, UEFI or legacy, you can skip to step 6.

The UEFI substage is for those installing in the modern UEFI 64 bit systems, while the Legacy mode substage is for those installing in the former/old systems with non UEFI partitions.

STAGE 1

0: backup the files in the removable storage, to avoid unnecessary data loss.

1. Goto start, type CMD or Command Prompt, rick click and run as administrator or ctrl + shift + left click / Enter.

2. In the command prompt window, type:
diskpart

3. List Disk
(Note the drive number of your USB disk)
select disk #
(where # is the disk number).

4. Type Clean
NB. This will erase all partitions and data on the USB

5. Type create partition primary

6. Type List partition
NB: If you did not skip actions 1-5, you should see only one partition here, and you can skip to  8.
Note the partition # of the partition and

7. Select Partiton #
where # is the partition #

as can be seen from the image aboove, cause I did a clean command, I have only one partition and the partition is selected by default (the * beside the partition name), so the List partition and select partition is not needed; but for those who skipped to this stage as a result of having multiple partition on their harddrive, they will see multiple partitions and can select the one they wish to format and use as bootable.

8. format fs=fat32 quick

9. active


10. assign

11. Exit

12. double click on the ISO image; or open the iso image with windows explorer (Windows 8 & above) and copy its content directly into the flash, or extract the ISO image with any of your favourite extractors and paste it's content into the USB disk.

IF UEFI ENVIRONMENT

If you're installing in a UEFI environment, If it's the new Windows 10, you are done already, if it is a windows 8 ISO image, continue with the additional steps below.

13. if you're installing from a 64 bit environment, goto EFI/Boot directory, if there is a bootx64.efi file in there, you need not worry anymore, you're done else;

14. locate and open install.wim in sources folder

15. copy bootx64.efi to the efi/boot directory of the USB removable disk

16. rename bootx64.efi to bootx64.efi.

17. Grab a drink, you're done.

IF NON UEFI / LEGACY ENVIRONMENT

For those who want to install in a non UEFI environment but the legacy/preUEFI days mode. follow the steps instead;

13.  Goto start, type CMD or Command Prompt, rick click and run as administrator or ctrl + shift + left click / Enter.

14.  type x: where x is the drive letter of the mounted ISO or of your USB removable disk. e.g d:

15. type cd boot to navigate into the x:\boot\ directory

16: type bootsect /nt60 d:
Where d: is the drive letter of your USB removable disk drive.