Re: What's openGL version?
I believe that card *should* support OpenGL 2.0. There are two recommendations I would have:
1) Install the proprietary nVidia drivers using System > Administration > Hardware Drivers
2) See if that works, and if it doesn't, type in a terminal "glxinfo | grep direct" to see if you have direct rendering. If it says something like "No. LIBGL_ALWAYS_INDIRECT set," see if you can get "glxinfo | grep direct" to work right by first typing "unset LIBGL_ALWAYS_INDIRECT." In most situations only applications launched by compiz (through keyboard shortcuts etc) will have this variable set, but I have seen it in other places.
To check your OpenGL version, type "glxinfo | grep -i opengl"
That should tell you both the OpenGL version you are using and what your card can support.
Intel core i5-2400, 8GB RAM, NVIDIA GeForce GTX 550 Ti