Fix for DLC2, delete appcache folder! The path is: program files->steam->appcache
Drag the 'appcache' folder to recyle ben while mw3 is off and restart mw3 steam will reinstall uncorupt folder! have fun :D

PLEAS READ CARFULY:
I have too many freinds on my friends list, therefore If your in one of my groups I am removing you from my friends list. These groups can be used just like a friends list simply press tab key then in steam in the lower left hand corner is a box that says friends at the bottom of that in the lower left hand corner of that box is a view all friends button click it and your friends list will open at the top part of your friends list is two tabs select GROUPS tab then next to our group click the pluss sign and the group will drop down like a friends list then find me with the star by my name as I am and always will be admin click drop down menue and join my game or send me message or whatever. ty :)