When HDD is down where the HDD is not detected, what we can do is to check the warranty, if still available, send back for RMA. But of course, your’re not able to get back your valuable data. If the HDD faulty due to the chipset, then u can still able to power on the HDD by exchanging the chipset behind the HDD. What u need is to get another extra chipset which is using same interface (SATA/IDE) for same series. So far i’ve tested only for exchanging chipset between same type of HDD. Not sure whether can work for different series.
Normally HDD screws are using special flower type, do not simply use screw driver that is not suitable to prevent spoiling the screw. After exchange chipset and able to power up and able to detect the HDD, u can backup your data. So, do not simple throw away broken HDD, maybe u can use it for recovering purpose in future.