I believe the system.management.instrumentation namespace provides classes to instrument an application. For example, if an application is stopped, an event will occur to get it started....

The problem is how to i determine the idle or unstable state of an application?

Welcome any advice

I've never used that namespace but my guess would be there is either some sort of property in that namespace that can tell you, or maybe one of the Application or Environment classes.

You might also have to fire the event yourself. I'm not sure. You just need to go read the SDK Documentation on that namespace for a little while and I'm sure you'll get the feel for it.