I have been working on my WP7 app now for around 6 weeks.  I’m not completely happy with it yet but I have good set of  base functionality.  For the first 4 weeks I couldn’t run my app in the emulator from the start screen or the app list.  I had to start the app from Visual Studio.  When I clicked the icon the screen would flash and return to the list/home screen.  I assumed this was an issue with the emulator but when I got a developer device I had the same issue.

I consulted with the connect.microsoft news group and at first we thought it was an assembly signing issue but one by one I eliminated them all as the cause.  Out of desperation I started a new project and slowly moved all my code to it and what do you know, it works.

I still have no idea what the problem was but at least its resolved.   Please leave a comment if your also having this issue and this fixes it.