This is a stub program that is embedded by the complier of 32 bit PE executables. It is inside the old MZ header section of the PE file, and is executed if you try to run the program under DOS.
It is possible to change the stub program. This is done using the /STUB option in MSVC++ 2005.
Under Project Properties=>Linker Options=>Command Line, type in:
...Where myprog.exe is a valid 32 bit PE executable.
Now, MSVC++ will embed myprog.exe as the stub program, instead, so you can do whatever you want...Perhaps display another message like:
DOS is dead! This game will not work for you, oldie.
This will probably be useless, but who knows.
Perhaps execute a different DOS version of the game, instead?