This guide will tell you how to TURN OFF Crosshairs & ADD Center DOT AIMING in Modern Warfare 2.
The first thing you will need to do is boot up your game, then press the Options button and click on Settings at the top of the options menu. After that, click on Interface.
Now you have to go to the crosshairs and turn it OFF. After this, scroll down and you will find an option for Center Dot under the Advanced Interface settings. You have to turn it ON, then navigate to the Center Dot Scale and set the size of the center dot.