With the continued use of your PC, its speed decreases especially those that have windows XP installed in them. The way to know this is by the computer taking longer than normal to respond to user actions like opening files, surfing the net and other normal tasks.
If you want to speed up the speed of your computer, that would be a brilliant idea. However, while dealing with computers caution should be taken not to harm your computer.

Overtime, as an operating system is a collection of files that perform different function, it can be possible that one of the files has been corrupted thus leading to slow response to the functions that it’s supposed to perform. one can then use the utility, system file checking, to inspect the files and correct any corrupted file,
As computers are vulnerable to viruses it would be advisable that one scans their computer for viruses from time to time as the viruses can also slow down the operation of your computer.
The other way would be to uninstall unused computer programs. Even though one does not use these programs they can slow down your computer as when the programs are installed they form a connection with the operating system.
Windows is known to provide a number of visual effects and if one does not have enough memory these effects are known to slow down the speed of your computer thus its advisable to adjust the visual effects from time to time to as it will make a difference.
Never to automatically start programs. These keeps them from loading at windows start up and speed up both booting and speed of your computer.
After you have tried everything else then you can defragment your hard drive. While doing these it’s advisable that one first backs up all his work and there is a reliable source of power.
If everything else has not worked then one can re install the operating system and programs. This is usually the best option if your PC is about three to four years old.
These steps will ensure that the speed of your computer is on point and one can be able to carry out his actions without having to be patient waiting for the computer to respond. Remember if you are not quite sure of how to perform any of the above functions its advisable to seek professional help.