Please use the correct terminology.

Both SATA & SCSI drives can be housed outside the
Computer, which makes them external, but not necessarily
removable (Hot Dockable).

While outside the "Physical" PC they are to XP, considered
to be a "Fixed"/(Internal) drive. They will not have the optional
Policy of optimizing for Fast Removal.

It is the REMOVABLE attribute that prevents XP from being
installed on a Drive/Flash device.

USB drives of any type are considered by XP to be removable.

"Carey Frisch [MVP]" <cnfrisch@nospamgmail.com> wrote in message
news:uAiNQKLEGHA.216@TK2MSFTNGP15.phx.gbl...
> Neither Windows XP or Vista (beta) can be
> installed and run from an external drive.
>
> Comprendo?
>
> --
> Carey Frisch
> Microsoft MVP
> Windows - Shell/User
> Microsoft Community Newsgroups
> news://msnews.microsoft.com/
>
> -------------------------------------------------------------------------------------------
>
> "liu" wrote:
>
> | It's a IDE drive turned into external USB drive connected through USB 2
> | port on a laptop.
>