Yeah. I'm not even sure you're at the stage of bootloader (GRUB) yet. Sounds like you have it installed somewhere, though.

Theoretically, your BIOS should be detecting your drive based on what is configured in the BIOS (regardless of anything actually stored on the drive, except for possibly its partition information). But, you have UEFI enabled, which is kind of like its own BIOS, so you may actually be seeing the drive through UEFI.

Actually, you said you had problems getting into BIOS - and if you are actually looking at BIOS now on a UEFI machine, you're definitely getting an incomplete picture of the system. You may need to disable Secure Boot or even disable UEFI altogether to allow Linux to have full access to your hardware. This link is kind of helpful in explaining, and has another link under the Disable Secure Boot section specific to linux installs. You may be able to find more information on Ubuntu regarding UEFI installs as well.