Ok, here's what you do. If you have United Offensive installed this may be tricky. Here's the steps:
1. Go to "My Computer".
2. Click "Local Disc (C
".
3. Click on the folder named, "Program Files"
4. Look for the folder named, "Call of Duty Game Of The Year Edition". click on it.
5. Look for a folder called, "Main". In it there should be a bunch of pak files. Do not delete. Look for ones that say stuff like "zzz_filename" or something like that. If it's a modern weapons mod, it should say modweps or something like that.
6. If you find it, make a folder of your desktop named, "Call of Duty Mods"
7. Place any mods in there.
If it's not in the main folder, do this.
1. Repeat steps 1 through 4.
2. Look for a folder like, "modweps" or something similar.
3. Repeat steps 6 and 7.
Once I get on my computer at home i'll post what files to keep and which ones to move to a mod folder on your desktop. If you have Call Of Duty United Offensive installed, make a folder named "Call of Duty: UO Mods" also for custom maps make one called "Call of Duty: UO Maps" and store and United Offensive maps or mods in there. Also, if you go to multiplayer options, there should be an option called "Enable Downloading". Click no to disable that. To avoid downloading them, in the menu that shows the servers, on the right there will be some servers with an "X". That means they are modded if you just want to play without mods avoid those servers.