It's not hopeless yet. The partition isn't destroyed just because GRUB bought the farm. You should really have tried to use boot-repair-disk with the password suggestions and not use the failsafe option. Failsafe goes for the first working OS in the first partition and stops looking. To detect Linux in a secondary partition and re-install GRUB you'd have to run the boot repair GUI. I'm quite sure it was root with no password.Azrial wrote: GRUB2 and Ubuntu Linux are both gone.
Otherwise if you have a bootable LIVE Ubuntu CD or USB, same utility:
Recovering Ubuntu After Installing Windows.
Or a Mint live CD or USB, look at this:
Restore Grub Boot Loader in Linux Mint After Installing Windows
Edit: oh wait, too late? You zapped Ubuntu and went with Mint?