“When your PC won’t boot from its hard drive, you might be dead in the water — unless you’ve created a bootable emergency repair disk or drive…even if you’ve diligently made system-image backups, you might still need an emergency disk at hand to restore the most recent image.” – Fred Langa

The links below present a really good two part series by Fred Langa in Windows Secrets.

It would be well worth your time to read them, and to prepare Rescue/Emergency Boot Disks for your computer.

Fred Langa does it by OS, starting with W8 through XP, and where to even get free Rescue Disks.

The second part is a detailed ‘how to’ and how to test the repair disk, change the boot order (two ways), how to work around W8 Secure Boot, and some advanced tips for W8 users.

Sources:

http://windowssecrets.com/newsletter/emergency-repair-disks-for-windows-part-1/

http://windowssecrets.com/top-story/emergency-repair-disks-for-windows-part-2/