I'm Confusing now , as i said before i choose GeForce 400 series and later because i think it's appropriate for my card but every time i reboot this message again appear ""the Propriety driver for your graphic card can not be found, the system is now using the free software driver (nvidia)"
I'm running the same kernel you are, so that shouldn't be a factor.
One thing I have done on this machine that may or may not have an impact is that I have removed all the Nvidia video drivers except for current - I got rid of 173 and the other one in Synaptic.
I want to say I had the same error with Nouveau being used come up, and I went through PCC, set the card to 400 or newer, saved it there, and now the only issue I have is after the GRUB screen the system claims it can't find a video output mode. I can either hit Enter and manually enter one for it to use, or just let it sit and it will boot on its own. Graphically everything works fine, and I'm using the Nvidia driver.
Did you enable desktop effects and secondary display in PCC?