Can't use my internal HDD as external HDD, Media is write protected!

Hi, everyone

i have 1TB external HDD and 600GB internal, so i have decided to swap them and make the 1TB as internal and the 600GB as external, when i plug the 600GB as USB to my pc it is shown as Unallocated, but when i try to format it it says " Media is write protected " so is the HDD physically write protected and there is no way to use it as external?

If it is not physically write protected, what could i do to be able to make it working? 

When i set it back as internal it works but i can’t format it, and it is shown as “system and primary in Disk management”

While the system is installed on the 1TB! I don’t know why it is shown as system!! and i guess this is why i can’t format it or use it as external!

Here is an image:

Any Idea?

thank you for your time, any help is greatly appreciated.

Hi WDTera, welcome to the WD Community. There are several brands and models for external hard drive enclosures, each one with their on list of compatible drives. 3rd party drive enclosures are not supported, but you can try to write zeros using DLG while the hard drive is connected directly to the PC motherboard. 

How to low level format or write zeros (full erase) to a WD hard drive or Solid State drive