>Hi there.  I'm still kind of new to scripting with Ruby.  I have
>written a small Ruby/Fox app that displays a message in a window at
>regular intervals.  The 'regular intervals' part is done using the
>Windows Task Scheduler.

>I'd like only one message window to appear at a time though.  What I
>am seeing is that if I step away from my computer for a few hours,
>there can sometimes be several of these popup windows on the desktop.

>I'd like the app to check (when it first starts up) to see if there
>are any other instances of this popup window on the desktop, and if
>so, just exit... or maybe kill the other window's process (I haven't
>decided which yet).

May be it's better to try another way:

1) Check that some file is being open or exists
2) Using Win32 API you can register unique objects that another instance
of your application is running (as far as I can remember they called
"atoms" in MSDN)
3) ... and so on. 

Finding a window isn't the only and the best way to check if you are
already running some process (it's platform dependent and there can be
another window with title 'foo').