To shrink a volume, follow these steps:
Open the Disk Management console.
Open the Control Panel.
Open the Administrative Tools window.
In Windows 7, choose System and Security and then choose Administrative Tools.
In Windows Vista, choose System and Maintenance and then choose Administrative Tools.
In Windows XP, open the Administrative Tools icon.
Open the Computer Management icon.
In Vista, click Continue or type the administrator’s password.
Right-click a volume.
It cannot be the system volume, such as drive C, or a media card, a flash drive, or an optical drive. It must be a hard drive.
Choose Shrink Volume from the shortcut menu.
Windows examines the volume to see how well it can be shrunk. Then it displays the Shrink dialog box where you can set the size of the new partition.
Set the amount of disk space to release.
Use the text box by the item Enter the Amount of Space to Shrink in MB to set the new volume size. The amount listed is 79103 MB, or just over 80 GB of storage. That’s also the maximum amount that can be shrunk; you can set the value lower, but not higher.
Set the size to whatever amount you need. Don’t restrict the existing volume too much, or else it may fill up and cause other problems.
Click the Shrink button to reduce the drive’s size.
The computer busies itself with shrinking the volume. When the operation has been completed, you see the new unallocated volume appear in the same slot as the current drive in the Disk Management console.