Hey there, miranSS.
Is that a new drive? If not, did anything in particular happen before this issue occurred? Would you please post a screenshot of what you see in Disk Management? Here's how to access it:
How to access Disk Management in Windows to manage hard drives.
You could try the drive with a different SATA port and different cables, or even better - with a different computer, to see if the same thing happens. If you don't have data to recover you could also download the HDD manufacturer's diagnostic tool and test it for errors and bad sectors, to see if anything out of the ordinary pops-up.
Hope that helps. Please let me know how everything goes.
Boogieman_WD