I have a toshiba satellite laptop that has an option to switch between UEFI and CSM/BIOS mode. I was able to successfully install 16.04 Ubuntu-Gnome in EUFI mode, but upon rebooting and selecting to boot from hard disk. I get an error informing me no bootable drive has been found.
What is the appropriate step to take to diagnose the reason I cannot boot from a successful Ubuntu-Gnome LTS 16.04 installation?