"Stretched" output from Acrobat Reader

Hello everybody. On my Compaq Presario 3240 laptop (which has a wide screen), Acrobat images appear stretched along the horizontal (wide) axis of the screen (wrong aspect ratio). I do NOT see this problem with any other graphics output; the aspect ratio of the icons on the desktop is fine, etc., EXCEPT when I view an image in Acrobat Reader. Although I am not absolutely certain, I think this started happening after I updated Acrobat Reader through YOU recently. Any suggestions? TIA. CF