Installing Ubuntu 14.04 LTS on Alienware 15 R3

Hi,

I tried to install Ubuntu 14.04 LTS as a dual boot on my Alienware 15 R3 by following this document (https://github.com/awesomebytes/alienware15r3_ubuntu14).

However, when I boot Ubuntu from live USB (which means "try Ubuntu without Installing"), Ubuntu gets low graphics mode and cannot go further.

I think this might be related to graphic card (GTX1070), but I am not sure how to fix it.

When I tried Ubuntu 16.04 instead, it successfully worked but I need 14.04LTS...

Do you have any idea?

My Alienware 15 R3 is

CPU: Intel R Core i7-7820HK 

GPU: GTX1070 8GB

Memory: 16GB DDR4 2400MHz (2x8GB)

Hard disk:  256GB SSD+ 1TB HDD

Thanks in advance