My laptop is currently running Windows 7 64-bit on a GPT disk. Instead of BIOS, the laptop also uses UEFI. After googling around, I cannot find any guide for this problem (maybe my googling skill is bad).
However, I just tried to install Ubuntu alongside with Windows 7 all by myself. After that, I couldn't boot to Windows. Luckily, I was able to fix that. Now, I want to find a guide to follow to make sure that there would be no problem.
EDIT 1: I found a guide here that suggests using Boot-Repair: - If you want to try grub-efi, it is first necessary to have a GPT disk with an ESP (EFI partition= FAT32, >200Mo, start_of_the_disk, boot flag), and to setup the BIOS in EFI mode. Then you need to install grub-efi (an easy way for this is to use Boot-Repair with the "Separate /efi" option). To finish, some old EFI-BIOS need to create an entry that boots the grub*.efi file in the EFI partition.
However, I still don't understand that I must install Ubuntu first (with a partition ? and a swap partition ?) then use Boot-repair or Boot-repair first ?