I installed Ubuntu 14.10 64 bit carried by USB stick in a laptop computer (ThinkPad X1 Carbon (2013) using both UFEI/legacy boot). It was a clean install with all the data erased inside the hard disk. The installation process was smooth until I reboot: instead of GRUB, I was directed in to a BIOS screen for choosing to boot from "ubuntu", my hard disk and "Windows recovery tool". There was no response in hitting all 3 options.
Then I re-install Ubuntu 14.04 LTS 64 bit with the same method. It was smooth and I was able to get in GRUB and then the OS. I upgraded the OS using the software updater and now I am able to boot into 14.10 without problem.
May I know the reason why this has happened?