Greyed Out HDD

Okay so here's my deal,

I have a hard drive that's worked for ages and it's in a very much healthy state( that's greyed out).
The drive is not accessible and Connor be located (it shows the drive in file explorer and disk management).


Now I do allot of music creating and I really don't want to lose the documents.

I have tried disk check it's in to performance with no errors detected.
I have also tried cdm checkdisk, changing letter of the drive.

I have tried to access this hard drive(external us 3.0 with Sebrent EC-HDFN)

The hard drive is a WD3200BPVT
320GB

It could be my Mobo that I finally put together cause the drives worked fine as well as several others that are now greyed out except for the main drive attached.

ATM I am installing Windows 10(fresh) onto another hdd to insert into my laptop and see what the drive does there.

I just wanted to know how does one backup these devices. Also how can this device do this if it has no errors, no bad sectors, or any such issues.

The laptop also couldn't access the device during boot up which would loop boot to recovery manager.
Recovery manager couldn't restore or anything. There is also no refresh only reset.

Thanks guys for looking into this.
I have done extensive online search but, nothing worked.

 

Update:
The hdd is greyed as well on another system. Still no errors or bad sectors.
Is there possible way off backing up. I need the document saves from my d.a.w.
Could careless about the rest.

Also I save and backup allot it's just idIonly back up the music mp3s. Need the audio workstation files as it's tons.