I made the mistake of installing Windows 10 after installing Linux (Kubuntu 18.04). How can I make Grub the controlling boot loader at this point without disturbing either of the existing installations?
Most of the discussion of this subject seems to assume that one or the other of the systems has been installed, but not both. If the existing setup boots into Windows, how do I get Grub installed? (I also have a live Kubuntu on a memory stick.)
Update: I've been able to get into my Kubuntu system by pressing Esc on power-up, which on this particular machine (HP Pavilion) gives me a choice of where to boot from. Kubuntu and Windows are the two important choices. But I still can't get the machine to boot directly into grub. I've installed and run Boot-Repair. It completed successfully but didn't solve the problem.
Further Update: I've finally gotten the dual boot to work, but I did it the scorched-earth way: I completely cleared the disk by installing a new partition table with gparted, reinstalled Windows 10 and then reinstalled Kubuntu 18.04. My conclusion is that if you're in a bad initial state, fixing the problem is almost impossible unless you have specialized knowledge. Most of the fixes proposed in this forum are dependent on a favorable initial state.
