When a file is too large to store in a single location on a hard disk, it is stored on the disk in discontiguous (not adjacent) parts or fragments. This fragmentation is "invisible" to the user; however. The locations of the fragments are kept track of by the system. Over time, disk access time can be slowed by fragmentation since each fragmented file is likely to require multiple drive head repositionings and accesses. (There's nothing you can do to prevent fragmentation, by the way.)

A disk defragmenter is a utility that rearranges your fragmented files and the free space on your computer so that files are stored in contiguous units and free space is consolidated in one contiguous block. This also improves access time to files that are now contiguous.

To defragment your hard disk:

1. Click Start
2. Right click My Computer
3. Right click the drive that contains the files and folders you want to check (normally C:).
4. Click on Properties
5. Click on the Tools tab.
6. Click on Defragment Now
7. You will have a choice to Analyze or Defragment. You can analyze first if you would like but eventually you'll end up clicking Defragment anyway.

To defragment your hard disk:

1. Double click My Computer icon
2. Right click the drive that contains the files and folders you want to check.
3. Click on Properties
4. Click on the Tools tab.
5. Click on Defragment Now
6. You may receive a message that reports the percentage of fragmentation. Go ahead and start defragmenter.

Note

• You can also start Disk Defragmenter by clicking Start, pointing to Programs, pointing to Accessories, pointing to System Tools, and then clicking Disk Defragmenter.

How often?? Strictly a personal preference. I haven’t found anything that recommends a specific time schedule. I recommend doing it regularly enough to prevent problems, 6 months seems to work well.