Touchpad mouse

I have a Latitude D520.  When I try to use the touchpad mouse, the mouse doesn't move in the direction that I move my finger.  If I go up and down, it goes side to side.  And if I go left and right, it goes up and down.  I have a wireless usb mouse that I normally use, but if I forget to take it with me, I want to be able to use the touchpad.  I tried changing the settings through the control panel, but nothing works.  Can anyone give me some advise, please.  Thank you.