In order for you to play Call of Duty: Black Ops II on Windows with minimal graphics settings, your computer must meet the following requirements
OS *:
Windows Vista SP2 or Windows 7.
Windows XP is not supportedProcessor (CPU):
Intel Core2 Duo E8200 2.66 GHz or AMD Phenom X3 8750 2.4 GHz
Memory (RAM):
2 GB for 32-bit OS or 4 GB for 64-bit OS
Graphics Card:
Nvidia GeForce 8800GT 512 MB or ATI Radeon HD 3870 512 MB
DirectX:
Version 9.0c
Hard Drive:
16 GB
Sound:
DirectX 11.0c compatible
Additional:
Broadband connection required for activation and multiplayer gameplay
Note:
Windows XP Operating System is not supportedFurther information:
Available here