How to Create Bootable USB Pen Drive Using Windows Command Prompt

To create a bootable USB flash drive

>> Insert a USB flash drive into a running computer.

>> Open a Command Prompt window as an administrator.

>> Type 'diskpart'.

>> In the new command line window that opens, to determine the USB flash drive number or drive letter, at the command prompt, type 'list disk', and then click ENTER. 

 The 'list disk' command displays all the disks on the computer. Note the drive number or drive letter of the USB flash drive.

>> At the command prompt, type 'select disk <X>', where X is the drive number or drive letter of the USB flash drive, and then click ENTER.

>> Type 'clean', and the click ENTER. This command deletes all data from the USB flash drive.

>> To create a new primary partition on the USB flash drive, type 'create part pri', and then click ENTER.

>> To select the partition that you just created, type 'select part 1', and then click ENTER.

>> To format the partition, type 'format fs=ntfs quick', and then click ENTER.

>> Type 'active', and then click ENTER.

>> Type 'exit', and then click ENTER.