Strange problem with launching Demigod and can't complete missions (sometimes).

I was searching this forum for a while but I didn't found anyone with such problem. I can only launch game just right after logging into windows, few seconds later I can't. To start the game i have to turn computer on again. Tried running it with that Stub file or something - didn't worked. I also have a problem with singleplayer missions. I passed some at the tournament, but sometimes I can't. At some point game stops counting kills, or points for domination etc. so I am unable to finish mission.