Shrinking a partition by using the GUI
1. First, like in most administrative tasks, you must be logged on as an Administrator.
2. In Windows Vista, go to Control Panel > System and Maintenance > Administrative Tools, or on the My Computer context menu. Select Computer Management. In Vista, if you are prompted for an administrator password or confirmation, type the password or provide confirmation.
3. In Windows Server 2008 you need to go to Server Manager, found in the Administrative Tools folder or on the My Computer context menu.
4. Next, scroll down till you get to the Storage section, and in it go to the Disk Management console.
5. Select the disk you want to shrink, for example Drive C.
Note: Shrinking any volume is fine as long as you make sure you leave enough space on the partition you are shrinking. For example, having a 40 GB system partition might seem too much at the beginning, but after a while you might find it to be less than optimal. You see, many applications such as Microsoft Office take tons of free space. So do Service Packs, hotfixes and other files. For a server running Windows Server 2008 this calculation might be different than on a workstation running Windows Vista, but in any case, make a mental note of this BEFORE shrinking your partitions.
6. Right-click the disk and select Shrink Volume.