How to Defrag a Computer

Learning how to defrag computer is one of the simplest maintenance tasks that can be done on a computer. 
The following methods of defragmentation are for Windows operating system users. For illustration purpose, I will explain using the example of Windows XP.

Defragmentation - How to Do It #1
This is the first (and the most common) method of defragmentation. Click on 'Start' at the bottom-left of your computer screen. Through 'Programs' and then through 'Accessories', navigate to the 'System Tools' folder. You will come across an application by the name of 'Disk Defragmenter' among the list of programs in the 'System Tools' folder. Click on that application. For your benefit, here is the path once again:

Start =>Programs =>Accessories =>System Tools =>Disk Defragmenter

Clicking on the application will open an application window. You can select a drive (for example C:\) and then click on 'Analyze' to find out whether that drive requires defragmentation or not. The graphical report that is displayed will give you an idea about the amount of existing fragmentation on that drive. Clicking on 'Defragment' will start the defragmentation process. This process can take a considerable amount of time (ranging from a few minutes to a couple of hours). For efficacy purposes, it is strongly recommended that you do not simultaneously execute any other applications or programs in the background, during the time that the drive is being defragmented.

Defragmentation - How to Do It #2
The second method is much shorter than the first. Click on Start and then click on Run. Type the words "cmd" and hit Enter. This will open a command prompt window. Type the words 'defrag', followed by a space, and the name of the drive that you wish to defragment, followed by a colon. For example, if you want to defragment drive D:\, you will have to type defrag d: and hit Enter. It will automatically initiate the entire defragmentation process, i.e. drive analysis + defragmentation.