X versus Y ruler lengths in corelDRAW 12

I recently moved corelDRAW 12 from a video monitor with an aspect ratio of 3X4 to a pc with an aspect ratio of 9X16. The only problem I am having is making the inch sizes in the Y direction the same as the X direction. I have tried changing the screen resolution and I tried measuring the rulers using the calibrate rulers function to no avail. If I draw a circle it displays as an ellipse with the vertical length shorter than the horizontal length. Is there a way to fix this problem or is it fixed in X3 or X4?

Thanks,

Richard Britton