Bootable Flash Drive

Some pre-requirements that you should be aware of:
1. Please make sure your PC support booting from flash - pen - key drive. If you have an older computer the bios may refer to your flash drive as USB floppy or USB zip drive. At this step you should operate some changes on your BIOS in order for you to boot from external flash drive.
2. Your flash drive must support booting.
3. Flash drive should have the system and boot files.
4. Flash drive should have a bootsector area.
Generally speaking you can have a bootable flash drive using this method

If you just want the short version of it, open a command prompt (cmd) in elevated mode and enter the following sequence of commands:

diskpart
list disk
select disk {number}
clean
create partition primary
select partition 1
active
format fs=fat32 quick
assign
exit

Replace {number} with the drive number. Just be sure that you double check the correct number of the disk.