For those having this issue, this is what I found that helps:

1. Computer Management
2. Device Manager
3. IDE ATA/ATAPI controllers
4. Properties
5. Driver
6. Update
7. Browse
8. Pick from a list of available drivers
9. Standart SATA AHCI Controller
10. Next, Close and Restart

For some reason, my HDD stopped getting disconnected, although it's still kind of slow.

For those having this issue, this is what I found that helps:

1. Computer Management
2. Device Manager
3. IDE ATA/ATAPI controllers
4. Properties
5. Driver
6. Update
7. Browse
8. Pick from a list of available drivers
9. Standart SATA AHCI Controller
10. Next, Close and Restart

For some reason, my HDD stopped getting disconnected, although it's still kind of slow.

EDIT: It was too slow so I had to buy a HDD rack and use it as an external hard drive. I really suggest this approach for everyone having this issue, since the rack is way cheaper than other solutions.