Update: We spoke with an Activision rep and they passed along the modern minimum specs needed for Modern Warfare 2 PC. Check it:
* OS: Microsoft Windows XP, Windows Vista and Windows 7 (Windows 95/98/ME/2000 are unsupported)
* Processor: Intel Pentium 4 3.2 GHz or AMD Athlon 64 3200+ processor or better supported
* Memory: 1 GB RAM
* Graphics: 256 MB NVIDIA GeForce 6600GT or better or ATI Radeon 1600XT or better
* DirectX: Microsoft DirectX(R) 9.0c
* Hard Drive: 12GB of free hard drive space
* Sound: 100% DirectX 9.0c compatible sound card
* Internet: Broadband connection required for Multiplayer Connectivity. Internet Connection required for activation
* OS: Windows Vista/XP
* Processor: AMD 64 3200+ or Intel Pentium 4 3.0Ghz or better
* Memory: 16 GB free hard drive space / 512 MB RAM (XP) / 1 GB RAM (Vista)
* Video Card: Shader 3.0 or better 256 MB nVidia Geforce 6600GT / ATI Radeon 1600XT or better