Dividing your hard disk into two or more logical storage units is called disk partitioning. On a partitioned hard drive, the drive letters (most often C, D, E and F) represent the different local disk partitions. Disk partitioning facilitates data storage and frees up system resources. Windows provides disk-partitioning capability through its disk management utility. You can both add and remove local disk partitions through this utility, but back up your important files before doing so.
Click "Start" (the Windows-logo button on the lower-left-hand corner of the screen)-->"Control Panel"-->"System and Security"-->"Administrative Tools." Double-click "Computer Management."
Click "Disk Management" on the left pane under "Storage."
Look at the different disk partitions in the middle of the screen.
Right-click on the disk partition you want to delete and select "Delete Volume."
Click "Yes" in the confirmation box to delete the disk partition.