Ubuntu 14.04 how to install cuda 6.5 without installing nvidia driver

I am working on workstation with CPU core I7 4790 and two GPUs GTX 760 4 GB ram/1152 core
the system's memory is 16 GB RAM
I have Ubuntu 14.04.1 LTS

after many tries and reinstalling Ubuntu many times finally i have correctly installed nvidia driver 340.46 using 3 shell commands ppa xorg-edgers

now i want to install Cuda 6.5 toolkit
but in the manual they say that the cuda toolkit installer will also install nvidia Graphics driver

how to prevent the installer from reinstall the graphics driver
how to install cuda 6.5 toolkit without reinstalling my graphics driver
because i faced many problems until i installed 340.46 correctly

and after successfully installing cuda toolkit 6.5 how to upgrade my graphics driver without disturbing cuda toolkit and reinstall everything from the beginning

Install aptitude

sudo apt-get install aptitude

and then run

aptitude

Click on Search type nvidia, use the arrow keys to go to nvidia-340.46 and click on Package and then Hold.

(and then still take a full system backup before installing CUDA; I use CloneZilla as a system backup: just take the / partition and leave the /home partition out! Works like a charm!)

Also, now you have aptitude, so even if things go wrong, you can still log into the console (Ctrl+Alt+F1) and use aptitude to delete whatever CUDA installed....