When you invite people over in your office and you run a pitch presentation on a 10 year old screen with a stretched aspect ratio, pixelated images, and burned in colours you are not leaving a very good impression.
LCD screens are not very expensive today, and the right cables plus a bit of tweaking with screen and laptop settings will give a razor sharp picture. Maybe it is time for a meeting room upgrade.
Other quick wins: removing used coffee cups, empty cookie boxes, de-greasing the screen remote, eliminating chewed-on pens and used stationary, open the windows.
First impressions count.