To get most out of defragmenting your hard drive:

- empty your recycle bin
- delete the temporary internet files
- run a registry clean

and only then defragment the hard drive. All versions of Windows have defragmenting tools, to open the disk defragmenter in Windows XP go to:

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

Select the drive you want and click the Defrag button.