in response to item #1 above: "If this is a simple DLL there is no way yet to run it from PHP."
Answer: There are several different packages/add-ons to php that enable low level access to the windows api. One of the most popular of these packages is available at http://www.winbinder.org
Winbinder does have the ability to load a dll and call it's functions. Winbinder also provides a large set of windows apis for creating windows and controls. This is useful for creating stand-alone desktop apps. It is a possible alternative to php-gtk.
I've had mixed results with Winbinder, some things work very well, others are buggy; source code is available. It's worth a look, Evaluate carefully.