I can't esc to Grub or anything. I simply get a black screen with one single '_' at the upper left hand corner of the screen.
Might have to flash your motherboards firmware, or possible storage issue. What are the system specs? What were you doing prior to the system crash? You may have to re-install your os on a separate partition after your bios recognizes your configuration, did you try running an ubuntu 18.04 usb repair disk utility? I recommend you take a look at these articles https://linuxhint.com/rufus_bootable_usb_install_ubuntu_18-04_lts/ and https://www.fosslinux.com/1521/boot-repair-for-ubuntu-linux-mint-and-elementary-os-can-fix-bootloader-issues.htm