Can I Repair Lubuntu 17.04 With Iso Disc?

Can I Repair Lubuntu 17.04 With Iso Disc? Backup partition table. Backup device boot sectors. Install GRUB bootloader. Configure GRUB bootloader. Add kernel options. Change the default OS in GRUB. Restore a Windows compatible MBR. Repair a broken filesystem. How do I boot Ubuntu as root? Hold ‘Shift’ while the machine is starting up to