Q: How do I record a demo of my game?

A: Simply type "/record <filename>" in the console to begin recording, and "/stoprecord" to finish. The lower left corner of the screen will display the size of the file during the recording.
Q: Where can I find my demo files?

A: The demo files will be stored in your "Call Of Duty 4/main/demos" folder
Q: How to I view my demos?

A1: The way it is supposed to work is that you type "/demo <demo-name>" in the console, but this is bugged and does not work (in version 1.4). Instead you can use a third party program to launch the demos, like COD4Player from Cybopat, which also allows you to change playback speed and camera angle. To stop the playback type /disconnect in the console
A2:

* Go to "C:\Program Files\Activision\Call of Duty 4 - Modern Warfare\Mods\ModWarfare" and create a folder called "demos". Open that folder and paste "test.dm_1". (your COD4 folder may be located differently)
* Open CoD4 Multiplayer back up, and click the Mods button at the main menu. Select "ModWarfare" and press Launch. Call of Duty should restart, this time with a blueish tint.
* Now, open up the console and type "/demo <demo-name>". Your demo will now be loaded and played back. There are no control functions (pause, rewind, etc.)
* Type /disconnect to close out of your demo.