O disco de reparação do sistema é usado para inicializar e restaurar a imagem do sistema a partir da unidade de recuperação. Paul Thurrott, da WinSuperSite, tem um bom artigo sobre o uso de um disco de reparo do sistema.
Windows 8 Dica: Use o Backup de Imagem do Sistema do Windows 7
Note that you’ll probably also want to create a system repair disk, which can be used to boot your PC and restore it using the system image backup you’re now creating, in the event of a hard drive issue or other hardware failure. I wrote about that process in Windows 8 Tip: Create Recovery Media. The recovery process has indeed changed in Windows 8, but it’s straightforward and, if anything, nicer than it was in Windows 7 … even if you use system image backups.