It is a tool that will try to restore Windows if you are not able to reboot it any longer. Once you have the Rescue CD with you, boot the affected PC from it, and follow the instructions.

Need installation media to reinstall Windows? Here's how to create a bootable CD, USB, or DVD with an ISO from scratch!

The procedure involved is: Download Windows ISO Create installer with Boot Camp Assistant ... “Create a Windows 10 or later version of install disk.” Deselect if there is n option to install ...