Call of Duty Modern Warfare
Saves | 002_killhouse-1

Instructions on using Call of Duty Modern Warfare saves:

1. Download desired Call Of Duty Modern Warfare save file to your desktop.
2. Extract the file, right click on SVG (savegame) file and select Copy.
3. Navigate to game installation folder and paste copied file to players/profiles/John/save/autosave/.
4. Open players/profiles/John/config.cfg file using WordPad and find this line:
seta sv_lastSaveGame "profiles/John/save/autosave/killhouse.svg"
Instead of "killhouse" (or whatever else is written there), enter the name of downloaded save file. Save the changes and exit WordPad.
5. Start your copy of Call Of Duty 4 Modern Warfare and click on "Resume Game"".

Game installation location:

C:\Program Files\Activision\Call of Duty 4 - Modern Warfare

For brand new game installation:

If you have a brand new game installation (which means you didn't play game before using downloaded savegame), it is recommended to start the game, and exit right after the first mission starts.
Do it before following the instructions above. This method will create necessary files within the game save directory.