I did a fresh install of Lubuntu 19.04 on my laptop. After installing core system on a C: drive with win10 and /home on another disk I successfully booted into the system. But after I edited background color and text color highlighted text color using a program called grub-customizer, I saved and rebooted. The thing is that after the bios image appears a black screen with a flashing underscore appears. I cant see any options, ALTHOUGH i can switch between win10 and lubuntu by using arrow keys, i dont see the options but i can navigate through them. Anyone has a solution?