Nvidia GTX-760...which driver?

[Lend27]

I'm having problems with some Steam games and thought it might help to try a later driver.
I found this:
http://linuxg.net/how-to-install-nvidia-...x-systems/

But after I run:  sudo /etc/init.d/lightdm stop   
the screen goes black to a flashing cursor and I am unable to execute the final command.
When I reboot I am back to the default driver.

After I stop X, how do I get to run that last command?
Thanks!
Len