I'm presently working on a project which involves switching a bunch of
applets from the old M$ Java runtime to Sun's 1.5 plug-in. We want to
be able to offer the users the chance to switch from the "old" applet
support to "new" applets and (and this is the hitch) back again, at
will, in case of problems.

So far, I have everything working beautifully, but I've struck a hitch.
If the user installs the JRE from the Sun site, it will by default turn
on applet tag support, which means that they are then stuck with the
Sun JRE no matter what until somebody switches it off. As we don't
really want the headache of having to explain to the users how this is
done, and as many of them may not even have local admin rights, I would
like to find a way of turning off applet tag support programmatically
from a signed Java applet.

The problem? The flag I need to hit is stored in the registry, not in
system preferences where (IMO) it should be. In
HKLM\Software\JavaSoft\Java Plug-in\(version)\UseJava2IExplorer.

Can anybody please suggest some way that I can reset this baby? Or am I
boned?

Many thanks for any and all suggestions,
Luke