So to restore you windows bootmanager you can run a simple command. I found this on Robert Penz Blog and it was so easy i really didn't think it would work. However this did work and the user was very happy to have his laptop booting again. (even if it is into windows) You will want to have the syslinux package installed. The linuxmint boot usb stick he had for me already had the tools so it was easy to work with.
sudo dd if=/usr/lib/syslinux/mbr.bin of=/dev/sda
And that's it. You will now have your machine booting again. There was a second solution