Problem with multi-byte text on Windows XP SP3

[Robert Inder (on Usenet)]

I'm currently having a problem with an HP printer and a laptop running
XP that has recently had SP 3 installed.

In diagnosing this problem, I have been looking at various ".INF"
files in C:\WINDOWS\INF, and found that the new ones now seem to be in
16-bit text.  I don't know if that is SUPPOSED to have happened ---
as I said, I'm having horrible problems with this laptop at the
moment.
But it has, so I'm trying to work with it.
When I open a recently-added ".INF" file in Notepad, it
looks fine and edits normally.  But when I open it in Emacs,
it looks like mince, with every other character being null (i.e.
^@ ).

Bargle!

A bit of guddling revealed that setting the file coding system to
utf-16-le-dos lets me see and edit the file OK.  But when I come to
write it, I get an error message:

    write-region: Symbol's function definition is void: utf-16-le-pre-
write-conversion

and the write fails.

I'm currently running Emacs 21.3.1, installed as a binary, probably
from alpha.gnu.org.

I see that emacs-23 is now on offer.  Will that fix the problem?
Do I need to upgrade to that?  Or is there some less drastic solution?

Robert.