DEFRAGMENTATION :

Over the time the files in hard disk gets fragmented with continuous use.

What is fragmentation?

First its important to understand how a data is stored in a hard disk.
Suppose we have a hard disk. over the time we have written some data and deleted some. the data we deleted may have been stored in some different parts. so although we have the free space, its not necessary that all that free space is together on the HDD. We have some pieces of free space here and some there. Now when a file of bigger size is to be written on disc and there is no "chunk" of space of that size available, the file is broken into pieces and the pieces are stored in different free space "chunks". Now what do we have? A single file which is broken into pieces and stored in some random places on hard disk. This is Fragmentation.
Obviously to access that that file we need to access all those pieces. this will slow your computer.

The solution to this problem is Defragmentation.

Windows comes with its own defragmentation utility.
You can work this from GUI interference in

start menu-->All programs-->accessories--> system tools-->Disk defragmenter

An important point to note before defragmenting is that you should have atleast free space 15% of the total space on that drive.

Or you can use From DOS. I'd prefer DOS way.
To defragment from DOS,

1.Open run in start menu and type cmd to open command prompt

2.First analyze if the drive is Fragmented enough for defragmenting. if you want to defragment d: type the command

defrag d: -a

this will give you the report of your drive.

3.if you large fragmentation, defrag using command

defrag d:

4.To force defragmentation even when there is not enough free space use command

defrag d: -f



CONVERT YOUR DRIVES TO NTFS

If you are still using FAT or FAT32 file systems, convert it to NTFS
Open command prompt and give command

convert d: /fs:ntfs (for converting d:)

If you try to convert C:(the windows partition) it will add a schedule task to perform the conversion on the next boot.


GET INTEL APPLICATION ACCELERATOR:

If you have motherboards with older intel chipset than 865. it is recommended that you download and install Intel application Accelerator from here .
This will replace the Default windows XP drivers of ATA hard disk and IDE drives with the new ones specially designed for intel chipset.

this will result in faster hard disk