Could you please give us a little more details about the issue? If you can copy files to the drive, it may have not been write protected. Please run the Command Prompt and type the following commands:
Select disk n (n is the number of the drive)
Check if write protection is enabled. I strongly recommend you to test the drive on another PC. Search the manufacturer’s web page for some formatting tool. I would update the antivirus and do complete system check just in case.
Hope this helps