I am using Lenovo Legion Y720 laptop. I have been using dual boot with Ubuntu 16.04 and Windows 10 for about 6 months now and have not had any problems. When I restarted my laptop this morning, it automatically logs into Windows 10 without showing the option (the dark pink screen - GRUB loader) to log into Ubuntu at all.
I tried going into UEFI mode by hitting Esc/Shift multiple times but neither of them works. It seems to me that the laptop is only detecting Windows as the only OS and not Ubuntu. I have important work saved onto my Ubuntu partition. Please help me in getting the Ubuntu working again. Thank you very much.