This tutorial is for how to defragment your hard drive, Its most commonly used just to speed up your computer.
Step 1) Go to Start -> All Programs
Step 2) Accessories -> System Tools -> Disk Defragmenter
Now ths Disk Defragmenter window should have appeared
Step 3) Now hit the Defragment button and it will commence! Just wait for it to finish and your disk defragment will be complete.