I just bought an iMac, and the cursor sometimes will go up and to the far extreme left, out of view, off screen. It happens quite frequently, sometimes I don't even need to touch the mouse and the cursor goes crazy. Also, this problem does not favor one side or another. Meaning it goes as much to the extreme left as it does the right. I don't know if there is some sort of software issue or if I should contact apple and get a new one <-- which is the way I am leaning.