Ok im really mad right now b/c for some reason MSDN keeps crashing my computer! So I was wondering if someone could help me figure this out. I was wondering how I would go about checking if another instance of my program was running, and could stop a second from being started. I have an idea, that you have to perform some kind of check before anything else like registering the window and such, but I have no idea how to implement this. Any help or links to code is much appreciated.