Well, if that box is coming up, it means your computer doesn't have enough memory, RAM, to do the job. It is telling you that you need to close other programs to free up space, otherwise it cannot do what you are asking it to. The jerkiness would be caused by your RAM being used at almost maximum capacity. That is also why everything takes so long to load. As to the multiple button hist, I sometimes have that problem, I think it is just a random occurence.