When your PC saves a large file to the hard drive, it breaks it into smaller pieces and stores them across several locations. This means the hard drive works slightly slower. Windows 7’s Disk Defragmenter tool reorganises this data in a more logical fashion, so your computer performs quicker. It can be set to run at scheduled times as part of your regular housekeeping cycle:

Click Start and type defragmenter in the search box. Click Disk Defragmenter from the results. Highlight the drive you want to defragment (usually the C: drive), then click Defragment disk. Depending on hard drive size and the number and type of files stored on the disk, it can take several hours to defragment the hard disk. However, you can still use the computer while Disk Defragmenter is running.