Well, that doesn't make much sense. void main() is not ANSI C if you meant it to be the entry point of your application if it were a console application.
But then you have the Windows GUI entry point WinMain(), but that one doesn't call PlaySound() so if your program is a Windows GUI (not console) application, the call to PlaySound() will never be because it is not anywhere inside WinMain().
Then there is this lonely "return 0;" line at the end that does nothing at all outside the context of a function. Are you missing a closing brace? That could be it.