Go to file and then to exit. Then you shall lose the game without blowing up.
This allows you to reveal the vast majority of Free Spaces (or in some cases, the entire field) in a single click. When setting up a Custom game, simply set the field size to a Width of 24 and a Length of 30 (or above). Then set the amount of Mines to 10.
Make sure the Minesweeper window is in focus, and then type the following code via the keyboard: xyzzy, ENTER, SHIFT.
Now when you start a game you will find a single pixel in the top left of the screen that indicates whether a mine is present on the square your mouse cursor is over. A black pixel represents a Mined Space, while a white pixel shows that the space is Free.
Note: It's been determined that Windows 95 and NT will not work with this cheat.