In rec.boats.cruising Jere Lull wrote:
:On 2007-10-16 02:05:28 -0400, "Alex"
said:

: To my knowledge, a Windows PC won't boot from an external hard drive.
: It will boot from an internal CD or DVD, but I don't think it will
: recognize a USB or FireWire remote drive.

:You've got to be kidding! I've been booting Macs from external drives
:from the early SCSI days, easily 15 years. Just hold down the "Option"
:key to get all the possible options, including net-boot. I thought
:Windoze had mostly caught up on trivial little things like that.

It's a limitation of the BIOS. If the BIOS properly enumerates USB
disks, windows will boot from them. Many don't, though things have
gotten better. I haven't tried in ages, though.