[Windows 10] Create Dual-Boot with Ubuntu on Alienware14

Hi,

I currently have an Alienware 14, with an intel i7, a GTX 765M and 8Go of RAM, and my computer is running under windows 10.

However, for my studies, I really need a Linux distribution and it has to run fast as I am often rendering some OpenGL things, I can not use a virtual machine anymore.

I mounted an USB Key using Unetbootin and I tried to install Ubuntu 14 and Ubuntu 15, booting into Legacy mode as booting into UEFI mode was not working at all.

During the installation, I did not have the "Install alongside windows" option, so, I just tried to create 3 partitions by myself, and the installation just went well.

However, after rebooting, I did not have the choice to boot either on Windows or on Ubuntu. I tried to follow what was said to fix this in this tutorial but it did not work.

I really tried several things and none of them work, I am just stuck now as I only have an Ubuntu version running under Virtual Box and it is now very efficient for what I am doing.

If someone has any idea that could help me, it would be very nice!

Thank You!