I don't know what's happening, but maybe I can make some suggestions that'll help you find the problem;
1) Make sure that both computers are running the same and latest patch for the game (
v1.61, maybe?)
2) Try starting a NEW game with your dad, and start playing from the beginning. If the crashes are
not occuring in this new game, then it may be that the game is crashing when certain content becomes available (
and the computer may be unable to display what needs to be seen - possibly graphics card related?). It may also be that the computer is somehow stretched to it's limit when too much of the world map is revealed and the game therefore becomes much more demanding. Assuming that the crashing does not occur in this new game, reload your previous saved game (
the one in which your dad and you were having problems) to make sure that the game does still crash.
3) It may be that later in the game, the graphics card (
or even SOUND card) is having great difficulty displaying what needs to be seen. On the computer that crashes, try turning off as much visual detail as possible. This means lowering the resolution to the lowest supported and disabling any 3D effects where you're offered the choice. Also turn off as much of the audio as possible - I'm not sure what options there are. You'll only need to do any of this on the crashing machine, obviously.
What is the specification of this computer ..? Also remember, you are doing the above ONLY in order to isolate the problem - we can then determine how to fix it properly (
turning off half the game is no proper solution).
Hope that's of use - let me know how you get on (
good luck) ...
