You can try basic a debugging technique: enter this line double d = document.parentWindow; Now, of course, this will not compile cleanly, and that is just what we want! Look at the error message and it will tell you that it can't convert from type zzz to double. (zzz will be a real type name, of course.) Now you know that this should work, so enter it: zzz z = document.parentWindow as zzz; Then try to proceed from there. One step at a time.

There is no easy little API call to make. This will require a black belt in Windows internals. Not all expose an API to tell you what files that app has open, and most apps don't expose any kind of API at all. You'd have to enumerate the handles of the process you're interested in, be it Word or Acrobat Reader. The problem is this technique is not documented anywhere, source code for it is very sparse, and it's all written in C++. You can find an example buried in the source for a Task Manager Extension, found right here[^] on CodeProject. RageInTheMachine9532 "...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome