After a regular upgrade on Linux Ubuntu Lucid 9.10, I was greeted with the following message:

You do not appear to be using the NVIDIA X driver. Please edit your X configuration file (just run `nvidia-xconfig` as root), and restart the X server.

I tried many forums to return this to normal. They seemed all too complicated and didn't solve the problem, more importantly.

Finally, I solved it by running a combination of commands from two different forums: (read more)