ZoomIt is screen zoom and annotation tool for technical
presentations that include application demonstrations. ZoomIt runs
unobtrusively in the tray and activates with customizable hotkeys to
zoom in on an area of the screen, move around while zoomed, and draw on
the zoomed image. I wrote ZoomIt to fit my specific needs and use it in
all my presentations.
Using the Windows key+U shortcut which launches the Windows accessibility interface is also another way to make your desktop easier to use if you are hard of hearing or of bad eyesight.