matt-icons_system-suspend-800pxApplies to: Windows 10. If you have Windows 8.1, 7 or Vista you should read about System Restore here.
Windows 10 System Protection (previously known as: System Restore) does not always come turned on as standard!

What is System Protection

“System protection is a feature that regularly creates and saves information about your computer’s system files and settings. System protection also saves previous versions of files that you’ve modified. It saves these files in restore points, which are created just before significant system events, such as the installation of a program or device driver.”[1]
Please note this is not a replacement to having a backup of your personal files, photos and documents.

Enable System Protection (or check if it is on)

  1. Open File Explorer from the start menu
  2. Right click on “This PC”
  3. Select “Properties”
  4. Select System Protection from the left hand menu
  5. Click on C: from the “Available Drives” list
  6. If it says “On” next to it then you can close down the screens
  7. If it says “Off” then click on “Configure”
  8. Select “Turn on System Protection”
  9. Click “OK”
  10. Then close all these windows by clicking OK or the red X in the top right of the window

For instructions with pictures, but in a bit more (too much?) detail click here.
Let me know how you get on in comments below or on The Clubroom.
Mike
[1] description taken from here.