I was reading a thread in here several pages back about some people having a problem with the game freezing at the black load up screen with the green progress bar getting about 1/3 complete then stopping.
I was having the same problem yesterday and from the advice in that thread, updated my video driver(Im using geforce 7600gs with XP) and after update and restart, game started fine. Well just tried the game today and did the same thing. I restarted my computer, but still locking up. I was trying to start the game from the start>all programs>AGEOD American Civil War>AGEOD American Civil War, BUT when I went to <start> and just clicked on the icon that is saved from previous games/programs that have been run, it fired right up.
Anyhow, maybe try that. Hope it works for those whom were having that same problem.