grub2 - Uninstalling grub after dual-boot

I tried to dual-boot Ubuntu 16.04 LTS with my pre-installed copy of Windows 10, but couldn't get it to work. Decided to delete the Ubuntu partition but I'm unable to uninstall grub completely.

Usually Windows 10 boots normally. But when the system wakes from hibernation(or dead battery), I'm greeted with the grub2 command line interface. Restarting the laptop lets Windows bootloader take charge again & boot normally.

I tried these things, but they had no effect:

• bootrec /fixmbr, /fixboot, \rebuildbcd all run successfully
  but do not solve the problem.


• Ran sudo lilo -M /dev/sda mbr from the Ubuntu live USB


• "Write MBR" via EasyBCD (not sure it was relevant but tried nevertheless)


• A tutorial suggested I removed the grub files altogether by mounting the EFI partition. Now waking after hibernation takes me to an "insert disk" screen; rebooting lets me use Windows again.

To summarize, Windows bootloader doesn't take charge when waking from hibernation but overrides grub otherwise. (This was the same issue I was encountering before uninstalling Ubuntu)

I finally installed Ubuntu to a USB instead. Made sure I selected the correct drive to install the bootloader. Aaaaand grub command-line is back. What's going on and how do I get Windows to boot normally?