One possible option is to check this thread and the one linked in it. This will permit you to detect if the application is listed among running applications in the system.
Another option, provided you can modify the target app or there already is some applicable function, is to use the interface that you are using to introduce some sort of "hartbeat" in the applications: the target appication periodically modify some element which can be handled in the interface so that your CVI app can detect it is alive.
