The Disk Defragmenter feature has been renamed as "Optimize Drives" under Windows
To defragment your hard drive under Windows 8:
- Click on the Charms Bar > Optimize Drives
- The Optimize Drives dialog shall open, displaying the list of drives.
- Select the drive of your choice (Note that: the Current status field will give you the % fragmented) and click on *Optimize.
- The defragmentation process will start.