Maybe open up File Explorer, or "Computer" so it shows all of the drives - This After you have attached the drive. Select the Drive, Right click on it, select "Properties" and go to Security options. Give the User full permissions to read the edit the drive. Seems like you have Admin only privileges on the drive, are you using a User account that is not an Administrator? Make a new local user account and give it full admin privileges, that should open the drive for you. Was the drive made on Windows 7? Sometimes the files and folders you made or even drives you have formatted under Windows 7 have different privileges than what Windows 8 gives them, I've had this happen for some of my folders where I was storing some junk.