Some of the nastiness aside from the others in plain terms the hardware you have isn't good enough for that game to run well. Ubisoft has a track record of making their AC games very demanding and not optimizing them for PC users and focusing on the console versions instead. From now on when you are thinking of playing a game you haven't played on that system yet head over to www.game-debate.com and create an account and log in, then go into the "Edit Rig" section and add your specs to it, then when you go and check on the system requirements of a game it'll give you green, orange/yellow and red check marks on things like the CPU, GPU and RAM requirements being cross checked with your system specs.