I was wondering how I can get the graphics card model/brand from code particularly from DirectX 9.0c (from within C++ code).
At runtime, you can query the device model and vendor:
In OpenGL, use the command glGetString(GL_VENDOR) or GL_RENDERER or GL_VERSION to get the information you're after.
In DirectX 9, it appears the info is in the Microsoft config system, and is queried from the device database. It's section 3 of this document, which also has example code: http://msdn.microsoft.com/en-us/library/bb204848(VS.85).aspx Using the same system you can get such information as the amount of ram the video card has, the driver number, etc.