How to correctly install nvidia drivers?

Question

first check you card to look for the adequate driver

    sudo lshw -C display

-display
description: VGA compatible controller product: G84GL [ Quadro FX 1700 ] vendor: NVIDIA Corporation physical id: 0 bus info: pci@0000:01:00.0 version: a1

add : deb http://ftp.debian.org/debian wheezy contrib non-free to /etc/apt/sources.list disable nouveau driver : add blacklist nouveau to /etc/modprobe.d/blacklist.conf proceed with the compatible version of the the driver

    apt-get update 
    apt-get install nvidia-version