Potential issue with margins

I've been working on my new site on a widescreen and just viewed my published version on my neighbor's not wide screen.
My pages did not adjust to her screen size, nor was their a scroll bar at the bottom of the window (weird).
Maybe this was an issue with her antiquated laptop?
Do I need to change the width of my design?
Would someone look for me?
Thank you
operatefromjoy.com