1. Copy all four folders (main, zone, mods, players)

2. Open your Call of Duty 4 game directory and paste them there. Overwrite the existing files (nothing is modified in the base game, so don't worry about making a separate game folder)

3. Find your iw3sp.exe in your Call of Duty 4 game directory, make a new shortcut of that file in your desktop, right click on that new shortcut and click properties. In the destination text, right after the game directory (when the final " ends) put ONE space and then this line: +set fs_game mods/spi_rooftops_main It should look something like this: "C:\Program Files\Activision\Call of Duty 4\iw3sp.exe" +set fs_game mods/spi_rooftops_main (Unless your game is installed somewhere else)

4. Launch the game from this shortcut

If you want to play the game without the Rooftops Campaign Mod, simply run the game without the shortcut you made.

STEAM USERS:

1. Right click CoD4 in your Steam Library and select Properties. Click Set Launch Options and paste this line: +set fs_game mods/spi_rooftops_main (Include the space before the command)

2. Run the game from Steam and it should work. If you want to play the game without the Rooftops Campaign Mod, just remove the line from Set Launch Options.