I have a problem that seems to have gotten worse with Windows 7 - I need suggestions - HELP!

My app is fullscreen and presents the user with a list of exercises to do. When user double click an exercise the app "launches" a new app that should appear over the top of the original app.

The problem I have is that a user can launch the exercise application but continue to click on the main application, the effect is that the exercise that is launched appears behind the main application and cannot be accessed unless the user does a alt-tab on the keyboard.

When the launch occurs I would like so that the zorder cannot be changed by use of a mouse button. i.e, the program that is launches always successfully starts infront.

Sounds simple but it is proving to be a pain to achieve any help or suggestions welcome.