Hi Sargemy
Could be low ram. I have xp and usually have as much as 1.4 gb of ram to play game out of 2 gb of ram. I also think that with vista you may need 3 gb of ram, rather then 2 gb. VISTA is a HUGE memory hog. I always play with 2 cpu's but when i start it sometimes gets laggy what i do is go back into 1 cpu apply then go back into 2 cpu's and apply, it clears for me. Let me know if it works good luck.