Ok. An explanation.

When you start old (16 bit) apps the operating system creates a safe environment to execute them in, and a process to do the thunking. These are your NTVDM and WOWEXEC threads.

Your application is started as another thread within the NTVDM process.

When you start another 16 bit app, it uses the existing NTVDM process (and WOWEXEC) to save memory.

When you close your 16 bit app, the OS may decide to leave the NTVDM process hanging around in case you start another one.

Now, I can think of a way of enhancing Rads suggestion to make it work for you.

Before I start on something that will take a while to put together, why don't you take a step back and explain exacly what it is you are trying to do, and why?

It may be that there is a far simpler way of doing it - looking for window titles, open files/shares etc.