How to make a bootable Windows 7 USB installer with CMD:

How to make a bootable Windows 7 USB installer with CMD:
  1. Open and run CMD as Administrator.
  2. Type Diskpart, press Enter.
  3. Type List Disk, press Enter.
  4. Type Select Disk # (where # is the number your USB drive shows up as), press Enter.
  5. Type Clean, press Enter.
  6. Type Create Partition Primary, press Enter.
  7. Type Active, press Enter.
  8. Type Format Quick FS=FAT32, press Enter.
  9. Type Assign, press Enter.
  10. Type Exit, press Enter.
  11. Copy everything from the Windows 7 installation DVD onto the USB key (a simple drag and drop will do; if you have an .iso extract or mount first).

ThinkPad T400S, hit F1 enter BIOS.

Make sure put USB HDD as the first priority of start up.