Note: Defrag may take as long as an hour or more if your data is very fragmented; Scandisk (the Standard option) should take only a few minutes.

Scandisk should be run no less than once a month, more often if you are a business or use your computer quite a lot. If you have many problems when running Scandisk (if the program seems to take a long time or starts and stops many times), your hard disk could be failing, and you may need to replace it. It may then be time to select the "Thorough" option (see below) to do a more thorough check of the magnetic particles on the surface of the platters of the hard disk. Most hard disks last about 5-7 years, but some new ones can fail immediately or in as little as a few months.

Defrag should be run no less than twice a year, more often if you are a business or use your computer a lot. If your computer seems to be slowing down noticeably, then it may be a good time to run it right away.
Click on Start—>Programs—>Accessories—>System Tools. Then click on one of the following, or click on their respective icons on the desktop, if they are on the desktop:

A. Disk Defragmenter
-this program moves your files and data around on the hard disk to speed up your computer’s accessing them.

1) Select the C:\ drive.

2) If the computer says that your C:\ drive is fragmented more than 5% or so, click on Start. Otherwise you can Exit the Defrag program, and wait until the fragmentation rate is above 5% before running Defrag.

3) If your hard drive is divided up and/or you also have a separate D:\ drive, then repeat the above for the D:\ drive (and the E:\ drive, the F:\ drive, and so on).

B. Scandisk-this program optimizes the directory and file system and cleans up sectors on the hard drive that contains data which no longer belongs to any program.

1) Click on the C:\ drive.

2) Click on Standard. (Thorough checks the magnetic particles on the hard drive’s platters and can take much longer to do, so it should only be done once every 9-12 months or so, unless you seem to be having problems with your hard disk.)

3) Be sure that the box next to "Automatically fix errors" is checked.

4) Click on the Start button.

5) Wait about 2-3 minutes for the Scandisk program to finish. Then click on Close. (If Scandisk takes longer than about 3 minutes, or seems to start and stop many times, then your hard disk may be failing and may need replacement.)

Note: Windows 98 has a program called Maintenance Wizard that can automatically perform the two task above on a regular schedule.