First of all are you sure it crashes or does it just freeze for an extended period of time? My computer does that alot. Sometimes it does just freeze for no reason and never gets unfrozen. I haven't found any ryhme or reasone to why it does this, I just restart it and try again till it works. Sometimes a sim file gets corrupt and it crashes when it trys to open it. If you can't get it to work at all, then maybe I'm not the person who can help you.