Another Call of Duty game that you are not vac banned on (Only Black Ops 1 has been tested so far, confirmation needed)
Call of Duty Black Ops II game files.
If you have these then you are ready to go!
Step one: Head over to your black ops 2 directory located in steam/steamapps/common/Call of Duty Black Ops II
Step two: Click one of the files and hit CTRL+A and then right click a file and select cut
Step three: Head over to your other Call of Duty game directory, I used steam/steamapps/common/Call of Duty Black Ops
Step four: Click one of the files and hit CTRL+A and then hit the delete key
Step five: Now there is nothing in the folder right click and press paste (Your other Call of Duty folder should now contain Black Ops II files)
Step six: Now hit CTRL+F and type t6zm (Zombies) or t6mp (Multiplayer) and hit enter
Step seven: Right click the file t6zm.exe or t6mp.exe and rename it BlackOps.exe (BlackOps.exe only works if you are replacing Black Ops 1 files)
Step eight: Head over to steam and run the call of duty you replaced and you are now playing black ops 2 unbanned!