Increasing memory usage each second

[KenH]

I have a MDI C# Windows form application that increases its memory
usage about 4k every second - even with all of the child windows
closed.
I have seen other posts about similar problems, frequently described
as memory leaks. Any ideas where to go to determine the problem with
the code would be appreciated
I consider the app fairly simple:
Midi app with four child windows. All windows have timers, either to
display time of day or the next time of day for a scheduled progress
to fire.
Each child has a couple rich text boxes, standard text boxes and a
status bar. In addition, each child has a Process control - used to
launch a communication tool every few hours.
Even if all of the child windows are closed, and the process controls
never started, the memory usage continues to increase.
My suspicion lies with the process control, but it is the reason for
the app to exist.
How can I determine what/where the issue is with the memory grab?

Thanks,
Ken