I have the same problem. It freezes during mission 2 in the campaign. I cant play any longer then 60 sec. I'm not sure what version i'm running but I'm downloading 1.57 at the moment. I have check my temps for all pc parts & all is running fine. My PC is more then enough to run ARMA II. I have tried a fresh install of Windows 7 64 and then a fresh install of ARMA II OA, & yet the problem still remains. I will install 1.57 tonight and try that but I dont think it will change anything by the sounds of all the other posts I have read. If anyone has the answer please let me know. I'm about to though this game out.