Windows Minesweeper

A secret cheat signal indicates whether a square is safe or mined.
This tiny warning-pixel sits in the upper left-hand corner of you screen and lights up white only when you cursor is over an unmined square.
To turn it on, type "xyzzy," then press [Enter], then [Shift].
The single pixel is hard to see unless you minimize everything but
minesweeper and use a dark, solid-colored Windows desktop.

---Or:
1. Click one square to start the timer.
2. Click and hold both the left and right mouse buttons.
3. While holding the buttons, press Escape.
This will pause the timer!
(Information from Cheat Machine)