For all demonstrators, especially teachers, sometimes need to zoom some points on computer screen to make small details get bigger. But Windows’s zooming solution is sometimes hard to use and crops a big area of screen. I think also Microsoft is not happy with their solution, at their site another program suggested: ZoomIt
ZoomIt is a really small program: almost 300KB! But this program gives us great zoom control on screen. ZoomIt does not only focus on some area, you can also give it a countdown timer on white groun to increase demontration performance.