Call of Duty 4: Modern Warfare is a first person shooter game for the PC, Playstation 3, Xbox 360, and Nintendo DS. All four platforms have multiplayer capability but only the PC, PS3 and Xbox 360 have the ability to play the game online.

Once you have it installed, to play Call of Duty: Modern Warfare offline, all you need to do is select the Go Offline option. This will let you boot up the campaign and get cracking with the story, simple as you like.