Installing Windows 7 on a USB drive (not install FROM usb but install TO usb) can be useful in some situations. Information on this process is very hard to find on the internet. Information can be found here:
However, after shutdown, attempting to boot from the USB drive gave the error “BOOTMGR is missing”. Steps to fix these errors can be found here:
Marking the C: drive on the USB disk as active, and then running “bootrec /fixboot” from the Windows 7 DVD made the installation work.
By: Neil Sikka