NVIDIA_SDK_7_0.exe is a software development kit containing various source code examples in DirectX and OpenGL.

FX_Composer_1.1.exe is a shader authoring tool based on DirectX HLSL; it comes with many shader examples.

Cg_1.2.1_Setup.exe is the installer for the Cg compiler.

Other useful software, as well as up to date versions of both the software above, can be downloaded from developer.nvidia.com.