For many years, Microsoft have offered “Disk Management” with it’s Operating Systems, which permits you to handle partitions. In preceding versions of Windows, you would need to delete the offered partition, and create a new partition in the exact size.

Here’s how to do it in Vista.

Click Start, Control Panel.

In the Control Panel there is a search box type in partition.

Double click on Administrative Tools (for preceding versions of Windows, click on “Computer Management” as well to access Disk Management).

Click on the partition you want to shrink and select Shrink Volume.

In the dialog box you need to enter the amount you want to reduce in size the hard disk volume by.

If the partition you want to shrink is 50 gig and you want to shrink that volume by 10 gig, enter 10000 (10240 to be exact) in the proper box.

Lastly, click at Shrink button. The process is very much alike if you would like to extend a partition, right click on the parition, followed by Extend.