// How to play
The board is the five-by-five block of cells C3:G7; a blue cell is a light that is on. Select a cell by clicking it (or move the selection with the arrow keys, as in Excel) and press the tall PRESS button: that cell and the four around it switch. Turn every light off to get GREAT! You did it! NEW GAME deals a fresh random board.
The macro also had its own shortcut, Ctrl+Shift+Q, which presses the selected cell straight away. It works here too, but some browsers keep that combination for themselves (Firefox, for one, can quit with it), so the button is the safe way.
// Revisited
Rebuilt in HTML5 + JavaScript from the VBA inside the original workbook (module Lights with CLEAR, MMM, MODi and CHECK_OUTCOME, the sheet's button code and Workbook_Open, 2008). The lights are the cells' own colour, Excel ColorIndex 5, and the column widths, row heights, fonts, borders, 75% zoom and the size and place of both buttons are read from the workbook. The new-game shuffle is the macro's own: it presses random cells in columns B to F, and since a press outside the board does nothing, column B never counts. That is kept as it was.
The Excel window around the sheet (menus, toolbars, formula bar, tabs) is a reconstruction for show, in the style of the Spanish Excel the game was made with. The sheet does not scroll, so the selection stays within the columns and rows you can see.