Panasonic Toughbook CF-30 – screen rotated and cannot undo

My wife placed a stack of papers on her open and running (win7pro) Toughbook CF-30. When she removed the papers the screen had been rotated 90 degress counter-clockwise. Turning the computer off and on does not reset the screen. I have searched for the key combination that has this effect and have not had any luck. Those few that I have found and tried do not work. Can anyone here provide an answer to reset the screen orientation to normal?