Step1. Open the command-line window by clicking “Start”, typing: “cmd”. In the command prompt, type ”diskpart”, press Enter
Step 2. At the Diskpart prompt, type: list disk and press Enter.
Then, all disks will be list at the prompt.
Step 3. Then, type: select disk X and press Enter.
X means disk number. Here, you choose the disk which has the partition you want to extend.
Step 4. Type: list partition and press Enter.
The partition(s) on the selected disk will be listed.
Step 5. Then, you can select the partition which you want to extend. Type: select partition Y and press Enter.
Y is the partition number you want to extend. Please make sure there is unallocated space behind the partition you want to extend.
Step 6. Type: extend size=Z and press Enter.
Z is the size in MB you want to add the partition.
