The best reason to partition your hard drive is to keep your software applications and operating system on your PC separate from your data files (i.e. music, pictures and other valuable documents you store on your computer).
A separate partition (separate parts of your hard disk) for all your precious files can give you a measure of protection from a corrupted operating system needing a fresh install on the C drive. Despite the wiping down of the C drive and the reinstallation of the operating system your files on the separate partition will be perfectly safe. However, if your hard drive fails totally, and is inaccessible, a separate partition will not save your files that is why we always recommend that you back up all your documents to another secure location (CD, DVD, Flash Drive or another physical drive).
Each partition is treated as a separate hard disk by your operating system and will be displayed with its own drive letter under My Computer.
If your hard drive is large enough additional partitions can be created and used to run multiple operating systems on your PC.
If you are running Windows Vista this has its own Disk Management Tool which can be used to partition your hard drive.
If you are running Windows XP we suggest that you use a third party tool to partition your hard drive such as Symantec Partition Magic or Paragon Partition Manager.
To use Symantec Partition Magic ( which is our preferred tool) download the software from Symantec.
Once Partition Magic is downloaded run the program. Tick the box to install it for All Users and then click on the dark green strip labeled Free next to the C Drive. Chose Create from the options at the top.
Accept the default Primary Partition setting and then select the Format Partition option and give it a suitable name, selecting NTFS as the format type. Adjust the partition size as you wish, then hit Apply.
Reboot your PC when prompted to do so. Once you are back in Windows you should see your new partition listed as a separate drive under My Computer.
To automate things a bit you should get your My Documents folder to move from the C drive to the new partition so that anything you save to My Documents will automatically will be saved to the new location.
To move My Documents click on the Start button and then right-click on My Documents and select Properties. If My Documents is not listed in your start menu then right click on the My Documents icon on your desktop instead.
When you've clicked on properties, select "Move" and then navigate to your new partition. Select the drive letter and then click "Make New Folder." Enter "My Documents" as the folder name and hit Enter and then OK. Windows will then ask you whether you want to move your documents. You do, so click Yes.
Moving your My Documents folder can take some time. Once moved, though, you can access the folder normally from the "My Documents" icon on the desktop, on the Start menu and elsewhere.
The ideal time to relocate your My Documents folder and other system folders is when you have just bought a new PC and have yet to load your data or applications. It's something to bear in mind when you buy your next PC.
For more information on moving your My Documents folder you can consult this Microsoft Support document http://support.microsoft.com/?id=310147.
Once you have moved your My Documents folder from the C Drive to your new partition you'll free up a lot of room on your C drive so its always a good idea to Defragment the C drive so that Windows can use it in the most effective way.