Stop Clock, Show Bombs:
Windows 95/98/NT

Once you have started a new game, click the left mouse button once, then click and hold the left mouse button, while still holding the left button click and hold the right mouse button and press 'esc' then let go of the mouse buttons. Bingo!! Timer Stopped

Windows 3.x
Minimise all applications except Minesweeper, during the game press in this sequence (without the talking marks) 'xyzzy' then press 'enter', Now when you hold 'shift' 1 pixel in the top left hand corner will change color showing if there is a bomb under your mouse cursor.