probrem with GRUB2, caot choose the OS.

Hello everyone.
I`ve got a PC with pre-installed Win 8 OS, later I upgraded it to Windows 10. One day I decided to try something new, and installed and Ubuntu 14.04 distro.
I booted it from the flash drive, succesfully installed it and rebooted the PC. The GRUB2 menu appeared, I chose Ubuntu and all was nice. The next day I tued te computer on, saw the loading screen and Win 10 OS without any choices.
I asked the question on the forum, serached some help in the Inteet and I found a post with the same problem: https://ubuntuforums.org/showthread.php?t=2272927
That was helpful, I loaded from the flash drive, used Boot-Repair, and it helped, but after reboot Win 10 loaded again.
When I tried to use Boot-Repair one more time, he wrote this:
GPT detected. Please create a BIOS-Boot partition (>1MB, unformatted filesystem, bios_grub flag). This can be performed via tools such as Gparted. Then try again.
I did what he asked me to do, and he again installed GRUB2 only for one reboot.
How can I install GRUB once and for a long time?
The first Boot Info Summary: http://paste.ubuntu.com/20745521/
The second one: https://yadi.sk/i/9V1R1o46tdVN3 (I don`t know why, but it was given to me as a text file)
Sorry for mistakes, English is not my native language.
Thanks in advance.