Pesky little Windows Boot Manager...
Been trying to install a new OS on my other laptop, but I wasn't sure if I should install the GRUB bootloader. So I skipped the step.
Turns out I do, because the Windows Boot Manager was getting in the way. Problem is, I didn't know how to go back to the installation page just to install the bootloader. So I had no choice but to redo the installation process.
I felt stupid, but I learned something new didn't I?