Dave has an excellent post on how to create a bootable USB drive for installing Vista or maybe Win 7. You could also use WinRAR to extract your ISO directly on to the flash drive (after formatting it as NTFS of course). A couple of points to remember though:

  • Make sure you use a “flash” drive (or USB stick) and not a USB HDD drive as some of those have issues with this.
  • Check different USB ports – all of them may not allow to boot up.