Boot repair asking for 64 bit iso - what do I do with it?

After downloading 64 bit boot-repair disk iso file, you have to burn it to cd or make a bootable Boot repair USB through unetbootin.

Then boot from the boot-repair live disk. Because you installed Ubuntu in UEFI mode, you have to give the partition where EFI files are located by clicking advanced option in boot-repair (not recommended repair).

Then run it. After the successful completion of boot-repair, shut down your PC and remove the boot-repair live disk.

Now change the boot order in BIOS to set HDD as the first option. Save the changes and exit out of the BIOS.

GRUB will appears on startup with all the OSs' entries.