I have an internal hard disk of 80 GB in it, I've installed Windows 7. In another External Hard Disk of 1 TB, I've installed Ubuntu 18.04 in a 125 GB Partition. Well this ext hard disk get faulty at times to my PC won't recognize it. When it's so, it is showing entering grub rescue mode and it waits for my command. So literally I can't go to Windows without my ext hard disk.
What I wish to do is to boot the Windows in my internal hard disk even when the external hard disk is unplugged.
PS I'm willing to reinstall my Ubuntu but I don't want to lose any data in my internal Hard disk.