clZoom is simple and portable utility that allows you to zoom in on your Windows desktop and magnify the pixels up to 16x.
Features include:

• Multiple monitor support
• Magnification from 1x to 16x, using mouse wheel
• Automatic refresh on timer, from 5ms to 10 seconds
• Automatic saving of preferences and window positions
• Very small in size
• Fully portable, can run from USB stick

Instructions :
Using your mouse click on the application window then drag the mouse outside and see the contents of the screen being magnified inside clZoom's window.
Use the mouse wheel to set the magnification ratio (1x to 16x). Set a refresh timer and get a constant magnifier on a chosen area of your screen. Download clZoom here