In Windows, there are accessibility options for people who may be hearing/sight impaired. All you have to do is click on the Start button, Programs, Accessories and then Ease of Access. In there, you can choose several built in programs that Windows offers for different impairments.
The one you're looking for is the magnifier. It allows a window to pop up that has an enlarged view of whatever portion of the screen your mouse is at.
Hope this helps!