1. This applies to a Sony (Vaio) laptop, although there are some general cmds/methodologies.
2. MAKE A COMPLETE BACK-UP OF YOUR C: DRIVE! Use the Sony Back-up tool. Back up to either an external HD connected to USB or DVD. The back-up will take about 16 GBs (obviously system dependent).
3. Go to the Command Prompt and type “diskpart” (if you’ve downloaded powershell – a very good idea – of course use it)
4. At the prompt type: “List Volume” Note which volume is your C: drive, mine was Volume 1…
5. At the prompt type: “Select Volume 1”
6. At the prompt type: “List Partition”
7. At the prompt type: “Select Partition 1” (Note there are two partitions (system dependent), one is 23 GB and the other is about 7 GB. Make sure you select the smaller parition which is labeled OEM.)
8. At the prompt type: “Delete Partition Override” – You have now deleted the partition which you selected above -it is now free to be allocated to other use. Without the “Override” sub-command the partition cannot be delete as it is protected. That is why you do not have access in Disk Management.