Procedure to Schedule Defragmentaton at Regular Intervals:

1. From the Windows desktop, click the Start button.
2. Click All Programs> Accessories> System Tools> Scheduled Tasks.
3. Double-click "Add Scheduled Tasks." This opens the Add Scheduled Tasks Wizard.
4. Click Next. Most of the programs in the program window you will see are things that you will never want to schedule regularly, and Defrag, which is good to schedule, is not on the list. You have to look for it, so click the Browse button.
5. In the "Select Program to Schedule" window, make sure the Look In: box is set to Local Disk C:> double-click the Windows folder> double-click the System32 folder> look for and double-click the file called "dfrg." This will cause the schedule window to appear.
6. Select a "radio button" to choose when to perform the defragmentation. Once a month would normally be OK, but once a week is good, too. You will probably find it inconvenient to defrag the drive when you turn on your computer since you will want to start work, so pick a time when you are more likely to not be using the computer; lunch time or at the end of the day or during the evening are probably good. Pick a button> click Next.
7. Pick the time, weekly interval, and day you want to run the defragmentation> click Next.
8. Enter the username and password of someone with administrative access to your computer so that the program will run. If you are at an office computer, you may have to get them to run this scheduled program for you. If you are at home, you probably have the ability to do this yourself. If you don't need a password to log on, you will not need a password to run this scheduled program> click Next.
9. Click Finish.

Follow-up Answer: When you do something with your computer, the computer opens up programs and data files by reading them from the hard drive and storing them into temporary random access memory (RAM). When it finishes with some of a program or some of the data, it puts the information back onto the hard disk. You may also create a new data file such as a Word document or download something off of the Internet and save the information on your computer, which means that it also gets saved on the hard drive.

Now, even though computers are normally considered to be logical, systematic, and orderly, it turns out that the information that gets returned to the hard drive frequently does not go back into the same place it came from. Not only that, different pieces of a file end up getting saved in different parts of the hard drive. As time goes on, your files on your hard drive get jumbled and fragmented on your hard drive rather than being returned in sequence and in order. What you get is called data fragmentation.