Visual Basic File debugs properly, but will not run in Windows

I have a very basic Visual Basic Pro开发者_JAVA百科gram that I created in Visual Studio 2010. It's a form application where clicking a button runs a simple calculation and then outputs the answer with MsgBox. When, I debug it works properly, however when I successfully build and run the exe, nothing happens. What could be going on here?

Are you doing anything like this?

Debug.Print(MsgBox("Your answer is 7.  Try again?", vbYesNo))

In other words, are you making use of a library that is only available to a debugging session (in this case, System.Diagnostics).