CTD at turn end

In my Romani campaign, I've reached 157 BCE and now, every time I try to click end turn, I get a CTD. I've checked all my provinces (all ~100 of them) and none of them are rioting. My theory is that my Empire has gotten so big that my computer ( a laptop which has only 1 GB of RAM) can't handle it anymore. I've tried playing it on another computer (a desktop which also has 1 GB RAM) and had the same result. Am I right to think that the poor RAM quality and the huge Empire combined to create the CTD's, or is there likely something else wrong? Thanks in advance for any help. -M