For some reason the XNA Game Studio doesn’t work on my PC. 🙁 . It says something about pixel shaders and my hardware doesn’t support something or the other. I just need to make some decent 2D games and demos. Neither do I think it will work on the PCs of my intended audience ( people from developing south-asian countries).
So is there any alternative for XNA that gives me equal performance and has a mature enough API?
You could check out Allegro (a game programming library)
Edit to provide more information:
Allegro 4 and 5 support the major OSs (Unix/Linux, Windows (MSVC, MinGW) and MacOS X). The engine supports 2D graphics primitives natively (you will need a separate API, like OpenGL or DirectX for 3D rendering, but you said that is not your target).