I don't know, I haven't dealt with Vista. But the fact that a Windows program runs under a clean DOS environment is a revelation to me.
Firstly, there's no need to distort words; no one was talking about a clean DOS. I was talking about a DOS emulator. As far as I know, Heroes I runs without problems on Windows 95, 98, and Millennium. I haven't tried it on Windows 2000, so I can't say. But on Windows XP and Vista, Heroes I doesn't run under normal conditions. And that's why an emulator is needed to run it, for example, (DosBox).
Secondly, Catch, if you know how to run Heroes I, at least on XP
haven't dealt with Vista