Open the bo2offlinespmpzmclientv37z.zip (or similar archive) and extract all contents directly into the root of your new Black Ops II folder.
Critical: Copy Master Server Fix files . Overwrite everything. bo2offlinespmpzmclientv37z install
You need the actual game data (T6 folder). Many users use files from the Plutonium Project or an existing Steam installation. Open the bo2offlinespmpzmclientv37z