Have you ever explored the options that Windows has to offer?  There are inbuilt assistive tools that give you and your students the opportunity to optimise access and active participation in learning.  Check out the options in Accessories or go to www.microsoft.com/enable/.  On the Microsoft site you can access tutorials, guides and video demonstrations on how to use the tools. 

Here is the thread to find these tools: 
1.    Start button
2.    All Programs
3.    Accessories
4.    Ease of Access folder
5.    Select Ease of Access Centre- 
        -    Magnifier
        -    Narrator
        -    Start On-Screen Keyboard
        -    Set up High-Contrast.

Enjoy the exploration and hopefully you and your students will benefit from these tools.