how to setup a usb drive to be bootable by cmd???

Follow these steps:
1) plug-in your USB stick
2) CMD run as admin privilege
3) Type Diskpart command
4) select disk 1 ( this will be the drive letter of your usb disk)
5) clean
6) create partition primary
7) select partition 1
8) active
9) format fs=NTFS QUICK
10) assign
11) exit
  Copy windows files to USB Drive and change
  Boot sequence in BIOS
ENJOY....:)