Maybe a tool like MHDD will get you going again. But that is not for the faint of heart. Then again, the drive is already a mess, so unintentionally adding more issues to it won't make the situation any worse.
The problem you describe, it does sound familiar in a way. the exact same thing happens here often, but then with pen drives...especially from the brand SanDisk (Cruzer Blade). Out of nowhere these just go into "media is write protected"-mode after 2 or 3 months and Windows isn't able to do anything with it anymore.
Almost like the operating system isn't registering those pen drives as a 'Removable device' from that point on. I would not be surprised if something similar is going on in the situation of the OP.
If You did not try this already, you could check if the drive is usable with an alternative operating system, such as Linux, Mac or BSD. Most Linux and BSD installers (ISOs) have an option to create a bootable medium with them, so you can try these OS'es out without messing with your currently installed operating system. If you do intent to try that, make sure you disconnect the drive(s) you normally boot from first. That way if you decide to use the format options in Linux or BSD, you won't format the wrong drive by accident.
Or try the drive in a USB hard disk enclosure. If you have a decent one, the hard disk controller inside that enclosure could "shake the drive loose" again for you.