Here you can turn on/off Automatically fix file system errors and Scan for and attempt recovery of bad sectors options.
Turning on of first option will repair any system errors. This errors can be happen with system files. Windows always using system files and for this reason, this Check will be made before starting Windows, when this files is unused. If turn on this option you will be prompted for scheduling this Check next time before Windows is start.
The second option mean that when you turn it on bad sector of your hard disk will be rescanned for recover possibility.
Now click on Start button like shown on the picture below.



