As you know, the Disk Management console tool in Windows XP will allow you to create a new partition using any unallocated, or free, space on a hard disk. However, if there is a single partition that takes up the entire hard disk, you can't use the Disk Management console tool to repartition the hard disk into two or more smaller partitions. If you want to accomplish this task in Windows XP, you will have to invest in a third-party console tool such as PartitionMagic. Of course you can back up the disk, reboot with a DOS startup disk, and then use DOS FDisk command to repartition the disk, but then you'll have to reformat and reinstall, which is a lot of work.
Fortunately, Windows Vista's Disk Management console tool will allow you to repartition your existing hard disk any way you want. In other words, it will now allow you to shrink, extend, create, and format partitions without putting your data in jeopardy. Of course, before you perform any of these operations, you should back up, just in case.
Click http://articles.techrepublic.com.com/5100-10877_11-6170510.html?tag=nl.e132to know how to repartition step by step