I have the 2015 students version of autocad for mac and after a few minutes of opening autocad, the screen gets full of vertical stripes and then on the screen apears a black bar in the middle of the screen and what was supposed to appear on the left side of the screen appers on the right and what should appear on the right side appears on left. Then if I close the autocad the screen is back to normal. What can I do to resolve this situation?