For a while, I was having the login problem where the computer would stop at the blue screen. I fixed this with the article on mac 101. However, now a blue screen will pop up seemingly at random, after a while of using the computer. This means that if I leave the computer on over night, there is invariably a blue screen up in the morning. When this happens I have to do a manual shutdown, and I can't save in any of my programs. Putting the computer to sleep prevents this from happening during sleep, but I don't want to do that *every* time I step away from my computer... Any help would be awesome.