emacs-home variable for Windows

[ken]

I carry a USB stick to the job.  It's got emacs installed on it and
there's a link on my desktop that I click (after inserting the stick)
and emacs fires up.  It's nice.  I use it every day.  With the paucity
of decent editors from Windows, I *need* it.

There's a couple minor hassles though that I'd like to dispense with.
One is that I don't know a way to tell emacs what the HOME directory is.
 In the past I've just gone into the registry and change some variable
there.  I don't remember where that is or how to do it though.  Besides,
I prefer to have the variable defined in my .emacs (which is at the
top-level directory on the USB stick).  (After emacs loads, I do "M-x
loadfile RETURN e:/.emacs" and that little task loads up the rest of the
stuff emacs needs to know.  But I don't know how tell emacs to make e:/
the home directory.

Anybody?

tia.

-- 
War is a failure of the imagination.
        --William Blake