If you don't Defrag your computer once a month then your computer may be not running as good/fast as it can. When you save, delete, add programs, or move files around, your hard drive gets fragmented. So when you try to access files or run programs it seems like it takes forever to find these programs or files. When you defrag your computer files and programs they are all lined up nice and neat for quick access. To do this defragment in Windows XP right click my computer, click manage, then on the list click on disk defragment then click defragment. If you have never defraged your computer this may take a while so turn it on before you go to bed and let it run all night. Also when you defrag, you shouldn't have any applications running.; You will notice a huge difference in speed when this defragmentation is done.