Friends, this post is specifically for people who are using Windows XP and want to repartition their Hard Drives without formatting them. All the Windows 7 & Windows Vista users can do it in a simpler way using Disc Management tool. For more info. you can visit the link: Repartition your Hard Drive w/o formatting it.
For all XP users, here’s the procedure:
When you buy a new computer, the hard drive partitions are usually already set up for you. If you put in a new hard drive, you need to decide on the partitioning at set up time. The problem with both of these situations is that things change. You may decide you don’t want everything in one big partition for a variety of reasons, but Windows gives you no options for changing your partitions other than reformatting and losing all of your data. There are excellent programs, like Partition Magic, that will let you resize and create partitions without losing data. But Partition Magic costs around $60 and it isn’t a program you are going to use everyday.
There is a way to change your partitions without reformatting and without buying any additional software.
It uses a Linux live CD to boot your computer and prepare for a Linux installation. Don’t worry; you are not actually going to install Linux. Every Linux CD includes a program to resize your Windows partition to make room for Linux because Windows usually takes up the whole hard drive. Once we create the space for Linux, we can actually format it as a Windows partition, either NTFS or FAT32.
First, you need to download the Linux live CD. I recommend Simply MEPIS 3.3, available here: . These directions will assume you are using Simply MEPIS. Download the ISO and burn it to a CD as an ISO image. Check your CD burning software for info on burning an ISO. Once you have your CD, you are ready to begin.
Before you start- it is recommended to do a disk clean up, get rid of unnecessary files and defragment your hard drive to create as much continuous free space as possible. If your drive is very fragmented, you may want to defragment twice.
WARNING- backup all important files. Although unlikely, it is possible to lose data. Even the programs like Partition Magic give you this warning.
Set your computer BIOS to boot from the CD drive as the first option. Most computers get into the BIOS by hitting the DELETE key during start up. The start up screen will usually tell you what to hit to enter set up. Look for something that deals with boot options; it is often under advanced bios options. Boot from the Simply MEPIS CD, choose the 2.6 option unless you have a CPU under 1Ghz. It will take a couple of minutes, but you will eventually have a sign in screen. Sign on as root with the password as root. It will boot to a red MEPIS Linux screen (actually running from the CD)

Click the K gear wheel (lower left). Move the mouse to System, File system, QTParted

Click on QTParted, that will open the program you are going to use.

Click on the drive you want to change. If you have only one drive, it will probably be /dev/hda. That will open a window with info about your hard drive. (My screen shot shows several partitions because I have Linux installed)

RIGHT click on the partition you want to resize and choose “RESIZE”. The free space will be created after the existing partition. Fill in the amount of free space you want. Remember to leave enough space on the existing partition for anything you may save in the future plus about 20% extra for free space. Then click OK.

No changes are being made to your hard drive yet, so you can change your mind. To make the change- click on FILE, the COMMIT.

The changes will be made to your hard drive. Click on your hard drive again in the left column. The free space should now show in the display in the right column. Right click on the free space, choose FORMAT, then either NTFS or FAT32. Click on FILE, COMMIT. The partition will be formatted as a Windows partition.

Shut down by clicking on the K gear wheel, logout, and restart.
Before it reboots, you will need to remove the MEPIS CD, it should now reboot to Windows, your computer will probably give you a message about new hardware being found and require you to reboot one more time. The new partition should now show up and be fully usable.