Connect Application and Application

Hi everyone

I have an vb application and I want to connect it to other Appication. For example when a user Open MS Word application I want my application start too and when they close that application my application close too.
Please help me how to do that? give me some example and code to do that. Thank you

New Peter :)

maybe u should like have your program active all the time...and in intervals check if Word is active...and only then..actually start your programs interface.