You can configure Minesweeper to display either a white or black pixel on screen, depending on if the cursor is over a mine (black) or not (white) by following these steps:
Start Minesweeper.
Type xyzzy, then press Shift+Enter.
Minimize all windows and begin play.
The pixel in the top left-hand corner of the desktop will be black if the cursor is over a mine square or white if the cursor is over a safe square. This trick works on all versions of Minesweeper supplied with Windows XP, Windows 2000, Windows NT 4.0, and Windows 3.1.