I was trying to install ubuntu 16.04.3 in dual boot mode on my PC which is pre-installed with Windows 8.1 by following this tutorial Everything was on its way, but suddenly ubuntu installer crashed at the point where we select nearest location/city.
Later I reinstalled ubuntu again, but it didn't helped me. When I start PC it starts in windows and if I reboot manually from USB from UEFI settings it again shows the options to Install Ubuntu and Try Ubuntu without installing. That means ubuntu is not installed properly I guess.
The Grub menu didn't launched at all.
I don't understand now what to do next. Windows partition looks like
I have disabled secure boot mode
and also turned off fast start-up
What to do in this situation? Please help me out. I want to merge all other windows partitions back to C drive and make it as a single partition again.