grub
Links
Reinstall GRUB - Linux Troubleshooting Guide: Fix the Most Common Problems
grubinstall.exe a GRUB installer for windows
LILO and GRUB: Boot Loaders Made Simple, O’Reilly, LinuxDevCenter.
Boot
Interrupt the boot process
If the GRUB screens are hidden during boot, hold down the SHIFT key until the menu displays. GRUB 2 searches for a depressed SHIFT key signal during boot.
Fix
Order
From How do I change the GRUB boot order?
Grub Customizer:
sudo add-apt-repository ppa:danielrichter2007/grub-customizer
sudo apt-get update
sudo apt-get install grub-customizer