Click in the bottom-left corner of the window.
A sudden power loss, virus attack, or failed software installation damaged the BOOTMGR file. Why You Should Never Download BOOTMGR Online
bootrec /fixmbr bootrec /fixboot bootrec /rebuildbcd
Run the following command (assuming C: is your offline Windows drive and D: is your system reserved/boot drive): sfc /scannow /offbootdir=D:\ /offwindir=C:\windows Use code with caution.