I have a white Macbook with Leopard and I didn't buy it new. I purchased it from someone who had it for about a year. Anyways, I was using it today, and suddenly my cursor started not moving, and then it disappeared off the screen. I decided to force shutdown and the screen turned to a white square in the middle of the screen with black edges. Also, I've taken the battery out, and tried to force restart, but it will only go into sleep mode and then when I turn it back on, it goes straight back to the white screen with black edges. I have no idea what the deal is, and have not seen anyone else having this problem. Please let me know if you have any insight on this issue. Thanks in advance.