Hi and thanks for the welcome! Hopefully I can contribute to help others also. My card is Nvidia GeForce 8400M GT, same as the thread starter, that's why I hijacked the thread!
I bought the laptop, a Sony Vaio VGN-AR41E back in 2007, so it's doing well! I have been to the Nvidia site and did the scan but when I try to install I get a message saying that no Nvidia device detected or words to that effect.
The Nvidia Site also advised downloading drivers
from Sony Vaio support, but I can find none.
So I was hoping I could install the original Vista drivers it came with. I have got these in C:/Drivers, which I think Windows creates during the upgrade process from Vista to 7.
As I sat, when I try this Windows says the best driver
is already installed, how can I override this?
The PC functions Ok without the Nvidia drivers but thing like Cover Flow in iTunes isn't supported as things are.