Ah... so others are experiencing similar incidents with or without wives sweeping dust into their PCs?
Curiouser and curiouser.....
EDIT: Okay... just ran CloD again and, halfway through Black Death the monitor went black like it had gone into standby mode. I could still hear the engines of the planes so kept pressing "Esc" to go back to the menu.... no result just endless engine noise.
I'm now not entirely sure I even want to risk playing this.