You can't unless you actually get 'Mods' from your computer or Laptop..
The is no Modern Warfare 4 you have the number in the wrong place The name is either COD 4 or Modern Warfare and the complete name is Call of Duty 4 Modern Warfare. There is no zombies for cod 4. There is only zombies for cod world at war and cod black ops. The games with the zombie mode are exclusion to Treyarch who developed the games for Activision
You cannot
Yes. Download zombies from the app store.
it has to be on PC and u just type in on developer hacks "UFO mode on"
usually treyarch bands the glitches online but in solo and split screen they cant band them. But u can find the on youtube. That's the basic source
Yes, no commando, or if there was a zombie mode (like Nazi zombies in CoD WaW)
Black Ops has a zombie mode
yes. it also has an extra mode where u can be the president
yes
yes ; watch syndicate and he has loads of videos of cod black ops zombies
Call of Duty 6(Modern Warfare 2) does not have a zombies mode in it.
You can get Nazi Zombies in CoD WaW on the PS3. If you are referring to CoD WaW as Cod 5, then your answer is yes. To get Nazi Zombies, simply beat the campaign on any difficulty.