The reason is that the built - in disk defragmenter in Windows won't start automatically and won't keep a tab on how much the disk is fragmented. (thewindowsclub.com)
We have read about Auslogics Registry Defrag when we saw some free Registry Defragmenters for Windows. (thewindowsclub.com)
If you want to defragment your hard drive on your own, just open the Disk Defragmenter tool and click the button to run a defragmentation operation. (howtogeek.com)