Process not ending when application closes

Hello,

This might be a stupid question, but I'm a rather novice programmer and I cannot find an answer to this issue that I'm having.

The application process will not die when I close the application. I have to manually end it in the task manager. I did a little looking on the web and read that all threads have to be closed before the main thread exits, but as far as I can tell, all threads are terminated when I close the application...yet the process persists.

What is even stranger is that if I start the application again without killing the original process, the second process that opens closes without a hitch when I kill the form...yet the first process (from the original running of the app) is still there.

Can anyone point me towards a resource that can tell me:
a) How to iterate through any possible active threads on the process to see if any are still alive
-and-
b) Why the first process will remain alive, but any further processes created by the application die normally when the form is closed.

Thanks in advance
Christoff

Also, the first process is using about 4K more memory than any of the subsequent processes of the same application that run while the first process is still active...this may not mean anything, but I figured I might as well list that as well just in case.