Just in case "scannow" indicates errors, but is unable to fix them, a deeper scan is needed by using the Deployment Image Servicing and Management (DISM) command tool.
- Open a command window AS ADMINISTRATOR
- Type: Dism /Online /Cleanup-Image /CheckHealth
When no errors are found, you're good to go.
When additional repairing is needed:
- Open a command window AS ADMINISTRATOR
- Type: Dism /Online /Cleanup-Image /RestoreHealth
After successfully ending of dism, you do need to do another sfc /scannow action to make sure everything is restored now.