Aspect ratio with E207WFP Widescreen LCD Monitor

I have recently got an Inspiron 530 quadcore running XP Pro with the E207WFP widescreen LCD monitor.

Overall, I am delighted with this system (apart from the lousy keyboard!), and the display is superb for both documents. BUT when photo editing, the aspect ratio of the widescreen means my pictures are unacceptably squashed such that precise editing is very difficult.

On widescreen televisions the aspect ratio can be changed according to the material being viewed.

HOW can I change the aspect ratio on my Dell monitor? On a TV you end up with a black stripe at either side. There is nothing obvious for this in control panels - display properties - settings.

Otherwise I may sell the widescreen monitor and go back to my old Dimension 20" Trinitron CRT: I haven't got room on my desk for both.