When GRUB fails, it's a horrible experience. Luckily it booted into rescue mode, and you can use that to fix the install:
https://help.ubuntu.com/community/Grub2#Rescue%20Mode
In my experience, Linux Mint doesn't install very well. On my old laptop it never booted the Live CD, and then when I got it to boot, the installation kept crashing. If you want your sister to use something easy, use Ubuntu.
https://help.ubuntu.com/community/Grub2#Rescue%20Mode
In my experience, Linux Mint doesn't install very well. On my old laptop it never booted the Live CD, and then when I got it to boot, the installation kept crashing. If you want your sister to use something easy, use Ubuntu.