I concur... Your teacher is up to his eyeballs in the bullsh!+. :) You may write and run any program you create on windows but without having the microsoft "endorsement" (IE: if you want the "made for windows xp" label or such) on your package, then MS won't guarantee it will actually run. But that's up to the programmer to verify. If you want that logo on your packaging then you have to follow some stringent guidelines and such... But even then MS doesn't have any right to your program or the right to change it. They may try to buy you out if it's good though. And that's what we all hope for. :)
Kanati
Kanati