In order for you to play Call of Duty: Black Ops on Windows with minimal graphics settings, your computer must meet the following requirements
OS *:
Windows® Vista / XP / 7
Processor (CPU):
Intel® Core™2 Duo E6600 or AMD Phenom™ X3 8750 or better
Memory (RAM):
2GB
Graphics Card:
Shader 3.0 or better 256MB NVIDIA® GeForce® 8600GT / ATI Radeon® X1950Pro or better
DirectX®:
DirectX® 9.0c
Hard Drive:
12GB*
Sound:
DirectX® 9.0c-compatible
*Call of Duty®: Black Ops requires an initial hard drive space of approximately 24GB to download and install the game via digital download (8GB of compressed files, 8GB of decompressed files and 8GB of installed files). Upon installing the game, 16GB (compressed and decompressed files) may be deleted from the hard drive. Please make note of where the compressed and decompressed files are being saved on your hard drive in order to later locate these temporary files for removal.