Incidentally, Emacs will use %UserProfile%\.emacs.d if you set %HOME% to %UserProfile%, which, as a UNIX user, I personally prefer for consistency. While not Emacs-specific, another trick I've found useful is that, on 64-bit Windows, you can open %SystemRoot%\System32\somefile in 32-bit Emacs iff you refer to it as %SystemRoot%\sysnative\somefile (the original path yields %SystemRoot%\SysWOW64\somefile).