Minesweeper secret

Instructions - 

Minimize or close all running applications. Launch Minesweeper, then type xyzzy. Next hold down either shift key for one second. Now when you move the mouse cursor over a Minesweeper square you will see a tiny white pixel in the top left corner of your desktop screen. 

This pixel will change to black when your mouse moves over a mine. You may need to change you desktop background to a solid color other then white or black to see the pixel.