You can reduce the size of an existing partition to create "unallocated space" or expand a partition if there is free space directly to its right.
Right-click the Computer icon (on your desktop or in the Start menu) and select Manage . In the left-hand menu of the window that appears, click Disk Management under the "Storage" section. disk management windows 7 download
Press the Windows Key + R on your keyboard to open the Run box. Type diskmgmt.msc and hit Enter. You can reduce the size of an existing