Call of Duty®: Black Ops Download Minimum System Requirements
* OS: Windows® Vista / XP / 7
* Processor:Intel® Core™2 Duo E6600 or AMD Phenom™ X3 8750 or better
* Memory: 2GB
* Video: Shader 3.0 or better 256MB NVIDIA® GeForce® 8600GT / ATI Radeon® X1950Pro or better
* Sound: DirectX 9.0c-compatible
* DirectX: 9.0c
Not mentioned is the fact you'll also need a Steam account to run the game, but really, who doesn't have one of those by now?