Your not getting steps in sitting in front of a monitor. Why the need to download on your PC? My S3 and my mobile get all my steps and workouts recorded no problem.
You could probably run it under BlueStacks or your Android emulator of choice on a PC. Not a native Windows solution, but it should run. The question is whether an emulated Android OS will allow communication to and from Samsung Health reliably enough through Windows? It might be a fight to the finish, or work like a charm.