Program won't open

I made a program recently and it will not start. It used to start up fine, but then it just stopped. Can someone please help me?

So what has changed to make it stop working?
-Did you maybe upgrade Visual Studio...add more code to the project...upgrade Windows(R)...anything?

Are you getting a compiler error? When you press the run/play button, NOTHING happens? Any error messages/warnings?

Have you used anything that would need a DLL?