According to the nVidia site, it should *easily* be supporting the 8400M, as that range of cards
Quote:
With support for Microsoft® DirectX® 10 Shader Model 4.0 and High Dynamic-Range Lighting (HDR), GeForce 8400M GPUs let you rip through all of today's most advanced and cutting-edge games and applications.
I am not sure why you are having to 'extract' files, can;t you just run the installer, or is there where it is having problems? If so, then delete the C:\Nvidia folder and try again....
According to this
Windows Vista and OpenGL-the Facts - OpenGL Pipeline Newsletter OpenGL works great on Vista....and according to the technical specs
GeForce 8400M - Technical Specifications it fully supports OpenGL through OpenGL 2.1