1. Open a Command prompt by clicking Start, typing command or cmd, and clicking Command Prompt.
2. Type: diskpart and press Enter.
3. Type: list volume and press Enter.
4. Type: select volume #, where # is the number of the drive that's giving you the "write-protected" error. In my case, I ended up typing select volume 3.
5. Type: attributes volume clear readonly and press Enter.
6. It should confirm: volume attributes cleared successfully
For more info type: help attributes volume