Hmmm. My machine doesn't have that registry key, and I don't have a
%JAVA_HOME% environment variable, but I definitely have the JRE
installed.

I just dug around, and I've got some stuff in
HKEY_LOCAL_MACHINE\Software\JavaSoft\Java Runtime Environment, but
it's just a folder with a single 1.6.0_23 subfolder. The subfolder
has a single "BalloonShown" boolean entry. Therefore, I suspect this
is a "settings" entry, rather than the official marker that the JRE is
installed.

I've got some other stuff beneath "Wow6432Node", but that doesn't
sound generic enough for my purposes.

Mike Hanson
www.boxsoft.net