I'm not sure how much DOS that a recent or current Windows operating system will emulate. A 32-bit console is available but it's not DOS.
Basically, just consider getting Visual Basic or Delphi and starting over. In fact a relatively simple Delphi 7 is still available when the current Delphi is purchased. But either Visual Basic or Delphi can easily make GUI's on Windows operating systems. Visual Basic or Delphi can also link to a DLL and use a DLL like a function.