How to defragment your c:\ drive

Modify the Disk Defragmenter schedule for the hard drive (C:) so that it is run automatically every Monday at 1:00 AM.

    
STEPS
TOOLS

In Windows Explorer, with the Computer window displayed, right-click Local Disk (C:), and from the shortcut menu, click Properties
In the Local Disk (C:) Properties dialog box, click the Tools tab. 
Click the Defragment now button. 
In the Disk Deframenter dialog box, click the Configure schedule button. 
In the Disk Defragmenter: Modify Schedule dialog box, click the Day arrow, and then pic a day.
Click OK button to confirm the settings.
Click Close button to close the dialog box.
In the Local Disk (C:) Properties dialog box, click OK button  to finish and complete and close the dialog box

 Windows OS