Heroes 3 issues under XP or Vista.

I don't want to change anything on my computer.

And we won't change anything. Just to understand the nature of the error, we need to eliminate possible causes. I might have overdone it with the sound card, but I'm quite serious about the video driver and DirectX – they need to be uninstalled and reinstalled.
Also, regarding the *Breath of Death* disc, the word "DOWNLOAD" is not welcome in this case – this is a forum where copyright is respected. If you had asked something via ICQ, I might have found a solution. And also, note that the first step is the *Breath of Death* disc – because there is a high probability that you simply have a pirated copy, which may be the cause of the problems... :)