Welcome to LinuxQuestions.org. Well, all that I can think about is that you are not using nvidia official drivers. The drivers that come with most distros are generic 2D drivers that only allow you to use your card without any TV-out or 3D acceleration support. Get into www.nvidia.com
and download the linux driver(IA-32 is most likely the one you want
). I never
recommend the latest one from Nvidia, they tend to be buggy, so grab the second newest one
Search the forum after Installing Nvidia drivers. It's pretty simple to install and there're plenty of threads regarding this subject. If you still get into trouble, post your problems here and we will try to help you!