I was able to successfully install Ubuntu 16.04.3 LTS on my HPPavilion laptop with Windows10 as the main OS. After Ubuntu installation, it asked to restart. After restart I do not get Grub menu, and it starts Windows OS. I tried disable secure boot, and lots of other things.
Note: I cannot access Ubuntu, so cannot access Terminal for commands.
I found https://www.supergrubdisk.org/ should I use this? or is there any other option?