i just got the Demo a few days ago and its a really fun game...but it crashed my computer 2 times. the game often freezes or just stops its process. should i not buy the game because i have Windows Vista....and if not and its safe to buy, will the game i buy act like the demo has for the last few days? i have a brand new  intel core 2 CPU 2.40GHz  2.39 GHz  2046 Gbs of ram  the best nvida card out their too...