Sudo grub-install dev/xxxy -force (xxxy determined by gparted)(sdc6 in my case)
This gave me grub menu and I pressed the first entry in it - “ubuntu” to boot normally.Booted ubuntu partition by Super Grub Disk.Steps followed in detail - First disabled fastboot of windows.
However, I am indebted to olfred as from his remark I guessed that I was wasting time with neogrub bootloader using grub4dos or Easybcd. So, it is not true what olfred remarked “I believe the bcdedit only works with UEFI.” Neither I updated the MBR of primary disk containing Windows 7 as it was the last thing I wanted to do. I have successfully booted Ubuntu 17.04 by creating an entry in the windows bootloader through bcdedit.
