1) I use 7.66 SP3, the most recent version. It's an Unhandled Exception error that crashes it upon loading Act 2. I tried to restart, only to find I'll have to kill Andariel all over again.
2) Every time I've tried to close it, the game closes as well. I don't mind leaving it open, but it's not necessary, IMO.
3) When I tried the restart to get the news about having to redo the final two Catacombs levels, it took eight tries to get it to finally run. Also took about 3-4 minutes each try, which didn't make me too happy either.