Cuda 7.5 install on Ubuntu 16.04

Hello
I have Quadro 2000 “http://www.nvidia.co.uk/object/product-quadro-2000-uk.html” and I spent the last two days trying to install Cuda 7.5 and I couldn’t, when I try to install I have this message (you are attempting to install on an unsupported configuration cuda 7.5). After a lot of work, I managed to install the GPU driver but the failed in the toolkit.
These are the pages that I followed:
https://askubuntu.com/questions/799184/how-can-i-install-cuda-on-ubuntu-16-04
https://askubuntu.com/questions/481414/install-nvidia-driver-instead-nouveau
https://askubuntu.com/questions/698488/installing-cuda-on-kubuntu-15-10-error-you-are-attempting-to-install-on-an-un
https://devtalk.nvidia.com/default/topic/831880/installing-the-nvidia-display-driver-/
The steps that help to install the driver was these:

sudo rm /tmp/.X*-lock
sudo apt-get purge nvidia-*
sudo reboot
sudo service lightdm stop
press alt+F1

log in

sudo rmmod nvidia
sudo sh cuda_7.5.18_linux.run
sudo service lightdm start

Note that it’s the third version of Ubuntu that I tried
Thank you

Ubuntu 16.04 is not officially supported by CUDA 7.5. I would recommend CUDA 8.

Yes, but according to Nvidia help team Cuda 8.0 does not support my GPU, and Matlab 2016 does not support Cuda 8, this is why I picked 7.5

CUDA 8 supports the Q2000.

If it’s possible as I’m new to Cuda, can you send me the link that shows that, please.
Thanks in advance

It’s OK if you don’t believe me. I’m not here to try and convince skeptics.

Sorry, I didn’t mean it that way, but I have more than one graphic card and that’s why I asked.