I played yesterday in multiplayer and downloaded many maps and today i wanted to play but then comes an error Couldn`t load default_mp.cfg. Make sure Call of Duty is run from the correct folder.
hmmm i am relatively new myself so I'm not sure if this will work, but it is safe to say that at least one of the maps you downloaded was corrupted or screwed up your game. Try uninstalling the maps and installing them one by one, you will probably find the culprit map. If that does not work try installing another copy (just run setup from the disk, ignore autorun) at another location and doing it all at a slower pace. :) hope this works. But remember, I'm not a professional.
the game CoD is looking for the cfg file, this one has been answered over and over. Your computer is looking for the cfg file thats located in: c:\program files\call of duty\main it sounds like you have the problem of the pc's settings are: c:\program files\call of duty/main
notice the end parts \main which it should be, and /main which could be your settings