I would download the game. It takes a lot of time, but still... As an alternative, I can suggest a complete system reinstallation (I know, I'm crazy, but this method always helped me).
:smile40: You're not crazy - this method has always helped me too... :smile04:
It's just a shame to have to "delete" everything again... :( Downloading Heroes? This could end with the complete "death" of the previously installed "Heroes 3"... Hmm... A difficult situation... We'll have to wait for the campaign to be reworked and the system to be updated...