Just Cause 2 System Requirements

Minimum:

OS: Microsoft Windows Vista (Windows XP is unsupported)
Processor: Dual-core CPU with SSE3 (Athlon 64 X2 4200 / Pentium D 3GHz)
Memory: 2GB System Memory
Hard Drive: 10GB of free drive space
Graphics: DX10 compatible graphics card with 256 MB of memory (Nvidia GeForce 8800 series/ ATI Radeon HD 2600 Pro)
Sound: 100% DirectX 10 compatible sound card
DirectX®: Microsoft DirectX 10

Recommended:

OS: Microsoft Windows Vista SP1 or Windows 7
Processor: Intel Core® 2 Duo 2.6 GHz or AMD Phenom X3 2.4GHz or equivalen
Memory: 3GB system Memory
Hard Drive:
Graphics: DX10 compatible graphics card with 512 MB of memory (Nvidia GeForce GTS 250 series/ ATI Radeon HD 5750 series)
Sound: 100% DirectX 10 compatible Dolby Digital 5.1 sound card
DirectX®: Microsoft DirectX 10.1