Call of Duty

Call of Duty is a first-person shooter video game developed by Infinity Ward and published
by Activision. The game simulates the infantry and combined arms warfare of World War II.
The game is based on the Quake III: Team Arena engine. It was accompanied in
September 2004 by an expansion pack, Call of Duty: United Offensive, which was
produced by Activision, and developed by Gray Matter Interactive, with contributions from
Pi Studios.

Call of duty can be purchased using Steam or buy it at Amazon

The installation of the game is fairly straight forward and the steps are spelled out for you mainly. :)