Just for the record, last night the game loaded very fast (making me think that something had been retained in RAM) and locked up almost at once, requiring a hard reset. After the reboot I ran it again and it locked up again, once more requiring a reset. The third time it ran perfectly.
I think that both crashes occurred when the cursor was on the edge of the 2D map ( I was trying to find the wagons mentioned in the Line of Operation thread I started a little while ago). On the third try, I moved around the centre of the map flicking between 2D and 3D before venturing to the edge (where the wagons were waiting - loved the silhouettes of the pack-horses in the distance, by the way.) I am not bothered that a demo crashes but it worries me that my PC locks up and I cannot even use ctrl-alt-del but must power it off.
These are the first crashes I have had with the demo.