Certainly! To know what is de-fragmentation or how does defragmenting your hard-disk improves performance, read more..

Your Hard-Disk is nothing but like a magnetic tape on which data is stored and the head moves over it to read the information stored there. Whenever you access a file, the head moves across the tape to the location where the data is stored and gets it for you. Imagine you delete a file, the particular part gets empty. Next when you store a file, the part that is empty is written first and then the rest on the next empty spot. Imagine if a file is stored part by part in different locations and each time you need to acess the file, the head wanders around making you loose a lot of time.

And here comes the de-fragmentation to help you out. De-Fragmenting your hard-disk will analyze your hard-drive for scattered files and bring them all stuck to one close location so the next time when you acess data, the head does not need to wander much thereby saving a lot of time boosing performance.

So I guess you now have got a clear picture of what disk de-fragmentation is.It is recommended you defragment once a while after using your PC for a long time. You can access De-Fragmentation from Start > All Programs > Accessories > System Tools > Disk Defragmentation

Before de-fragmenting your hard-disk, it is also better to do a system cleanup.