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?

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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).