New PCs are often equipped of the UEFI(Universal EFI) capable booting. Some SSD drives will even not boot in Linux the Legacy MBR mode. So in order to make the PC boot properly we need to:
– Create an EFI Partition
– Install GRUB(Boot loader) on it

Create the EFI Partition:
Create an EFI capable Boot partition of 200MB as first Partition before installing the Debian/Ubuntu system

# gdisk /dev/(boot disk)
From inside gdisk:

Installing GRUB on a EFI system

Start a live system from a liveCD or an USB Drive.
From inside the live system:

Login as root
Mount the installed system on /mnt and chroot to /mnt
# for i in /dev /dev/pts /proc /sys /run; do mount -B $i /mnt$i;done; chroot /mnt
# . /root/.bashrc
# apt-get install grub-efi
# mkdir /boot/efi
# mount /dev/(EFI Partition) /boot/efi
# grub-install --target=x86_64-efi /boot/efi
# update-grub

Also see: